I LI BRARY gF CO NGRESS, 



{UNITED STATES OF AMERICA. 



HOW CROPS GROW. 



>wf^ 



A TKEATISE ON THE 



CHEMICAL COMPOSITION, STRUCTURE, 
AND LIFE OF THE PLANT, 



ALL STUDENTS OF AGRICULTURE. 



WITH NUMEROUS ILLUSTRATIONS AND TABLES OF ANALYSES. 



SAMUEL W. JOH^NTSON", M. A., 

PROFBSSOE OP AJTAIiTTICAL AKD AGElfcuLTTTEAL CHEMISTKT IK THE SHEFFIELD 

SCIBNTrPia SCHOOti of YALE COLLEaS; CHEMIST TO THE COKNEC- 

TICUT STATE AGBICtTLTUEAI. SOCIETY; MEMBER OP THE 

NATIOXAi ACADEMY OP SCIENCES. 




/^ 



-. KEW YORK: 



ORANaE JUDD & COMPANY, 



245 BROADWAY. 



Entered according to Act of Congress, in the year 1868, by 

ORANGE JUDD & CO., 

At the Clerk's Office of the District Court of the United States for the 
Southern District of New-York, 



LovEJOY, Son & Co., 

Electrottpers & Stekeottpers, 

15 Vandewater Street, N. Y. 



PREFACE, 



For the last twelve years it lias been the duty of the 
writer to pronounce a course of lectures annually upon 
Agricultural Chemistry and Physiology to a class in the 
Scientific School of Yale College. This volume is a result 
of studies undertaken in preparing these lectures. It is 
intended to be one of a series that shall cover the whole 
subject of the applications of Chemical and Physiological 
Science to Agriculture, and is offered to the public in the 
hope that it will supply a deficiency that has long existed 
in English literature. 

The progress of these branches of science during recent 
years has been very great. Thanks to the activity of 
numerous English, French, and especially German inves- 
tigators. Agricultural Chemistry has ceased to be the 
monopoly of speculative minds, and is well based on a 
foundation of hard work in the study of facts and first 
principles. Vegetable Physiolagy has likewise made re- 
markable advances, has disencumbered itself of many 
useless accumulations, and has achieved much that is of 
direct bearing on the art of cultivation. 

The author has endeavored in this work to lay out a 
groundwork of facts sufficiently complete to reflect a true 
and well-proportioned image of the nature and needs of 
the plant, and to serve the student of agriculture for 
thoroughly preparing himself to comprehend the whole 
3 



IV now CKOPS GROW. 

subject of vegetable nutrition, and to estimate accurately 
how and to what extent tbe crop depends upon the at- 
mosphere on the one hand, and the soil on the other, for 
the elements of its growth. 

It has been sought to present the subject inductively, 
to collate and compare, as far as possible, all the facts, and 
so to describe and discuss the methods of investigation 
that the conclusions given shall not rest on any individual 
authority, but that the student may be able to judge him- 
self of their validity and importance. In many cases ful- 
ness of detail has been employed, from a conviction that 
an acquaintance with the sources of information, and with 
the processes by which a problem is attacked and truth ar- 
rived at, is a necessary part of the education of those who 
are hereafter to be of service in the advancement of agri- 
culture. The Agricultural Schools that are coming into 
operation should do more than instruct in the general re- 
sults of Agricultural Science. They should teach the 
subject so thoroughly that the learner may comprehend 
at once the deficiencies and the possibilities of our knowl- 
edge. Thus we may hope that a company of capable in- 
vestigators may be raised up, from whose efforts the 
science and the art may receive new and continual im- 
pulses. 

In preparing the ensuing pages the writer has kept his eye 
steadily fixed upon the practical aspects of the subject. A 
multitude of interesting details have been omitted for the 
sake of comprising within a reasonable space that informa-' 
tion which may most immediately serve the agriculturist. 
It must not, however, be forgotten, that a valuable principle 
is often arrived at from the study of facts, which, consid- 
ered singly, have no visible connection with a practical 
result. Statements are made which may appear far more 
curious than useful, and that have, at present, a simply 
speculative interest, no mode being apparent by which the 
farmer can increase his crops or diminish his labors by help 



PEEFACE. V 

of his acquaintance witli them. Such facts are not, how- 
ever, for this reason to be ignored or refused a place in our 
treatise, nor do they render our book less practical or less 
valuable. It is just such curious and seemingly useless 
facts that are often the seeds of vast advances in industry 
and arts. 

For those who have not enjoyed the advantages of the 
schools, the author has sought to unfold his subjects by 
such regular and simple steps, that any one may easily 
master them. It has also been attempted to adapt the 
work in form and contents to the wants of the class-room 
by a strictly systematic arrangement of topics, and by di- 
vision of the matter into convenient paragraphs. 

To aid the student who has access to a chemical labor- 
atory and desires to make himself practically familiar 
with the elements and compounds that exist in plants, a 
number of simple experiments are described somewhat in 
detail. The repetition of these will be found extremely 
useful by giving the learner an opportunity of sharpening 
his perceptive powers, as well as of deepening the impres- 
sions of study. 

The author has endeavored to make this volume con> 
plete ia itself, and for that purpose has introduced a short 
section on The Food of the Plant. In the succeeding vol- 
ume, which is nearly ready for the printer, to be entitled 
"How Crops Feed," this subject will be amplified in all 
its details, and the atmosphere and the soil will be fully 
discussed in their manifold Relations to the Plant. A 
third volume, it is hoped, will be prepared at an early day 
upon Cultivation ; or, the Improvement of the Soil and the 
Crop by Tillage and Manures. Lastly, if time and 
strength do not fail, a fourth work on Stock Feeding and 
Dairy Produce, considered from the point of view of 
chemical and physiological science, may finish the series. 

It is a source of deep and continual regret to the writer 
that his efforts in the field of agriculture have been mostly 



VI HOW CEOPS GEOW. 

confined to editing and communicating the results of tlie 
labors of others. 

He will not call it a misfortune that other duties of life 
and of his professional position have fully employed his 
time and his energies, but the fact is his apology for be- 
ing a middle man and not a producer of the priceless com- 
modities of science. He hopes yet that circumstances 
may put it in his power to give his undivided attention to 
the experimental solution of numerous problems which 
now perplex both the philosopher and the farmer ; and 
he would earnestly invite young men reared in familiarity 
with the occupations of the farm, who are conscious of 
the power of investigation, to enter the fields of Agricul- 
tural Science, now white with a harvest for which the 
reapers are all too few. 



ACKNOWLEDGMENTS, 



The author would express his thanks to his friend Dr. 
Peter Collier, Professor of Chemistry in the University 
of Vermont, for a large share of the calculations and re- 
ductions required for the Tables pp. 150-6. 

Of the illustrations, fig's 3, 4, 5, 7, 47, 63, and 64, were 
drawn by Mr. Lockwood Sanford, the engraver. For oth- 
ers, acknowledgments are due to the following authors, 
from whose works they have been borrowed, viz. : 

ScHLEiDEN.— Fig's 10, 13, 17, 19, 30, 48, 49, and 50, 
Physiologie der Pflanzen und Thiere. 

Sachs. — Fig's 56 and 65, SUzungsherichte der Wiener 
Akademie, XXXYII, 1859, and fig's 22, 38, 40, 41, 42, 
43, 59, QQ^ 69, 70, and 71, Exxoerimental-Physiologie der 
Pflanzen. 

Patent. — Fig's 11, 12, and ^Z^ Precis de GMmie Indus- 
trielle, 

DucHARTEE. — ^Fig's 60 and 61, J^lements de JBotanique. 

KiJHN. — Fig's 18, *21a, 29, and 34, Ernahrung des 
Mindviehes. 

Hartig. — Fig's 20, 21b, 32, EntwickelungsgesGhichte 
des Pflxxnzenhei'ms. 

TJngee. — Fig. 26, SUzungsherichte der Wiener Akade- 
mie, XLIII, and fig. 55, Aiiat. u. Phys. der Pflanzen. 

ScHACHT. — Fig's 33, 37, 44, Anatomie der Gewmchse, 
fig's 51, 53, 54, and 62, Per Baum, and fig's 52, 57, and 
58, Pie Kartoffel und ihre KranJcheiten. 

Henfrey. — Fig's 36 and 39, Jour. Boy. Ag. JSoc, of 
England, Yol. XIX, pp. 483 and 484. 
7 



TABLE OF CONTENTS. 

Intkoductiok iTf 

DIVISION I.— CHEMICAL COMPOSITION OF THE PLANT. 

Chap. I.— The Volatile Part of Plants 28 

§ 1. Distinctions and Definitions 28 

§ 2. Elements of the Volatile Part of Plants 31 

Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur, Phosphor- 
us, Ultimate Composition of Oi-ganic Matter 45 

§ 3. Chemical Affinity 46 

§ 4. Vegetable Organic Compounds or Proximate Elements 52 

1. Water 53 

2. Cellulose Group 55 

3. Pectose '' 81 

4. Vegetable Acids 85 

6. Fats 89 

6. Albuminoids 94 

Appendix, Chlorophyll, etc 109 

Chap, n.— The Ash of Plants Ill 

§ 1. Ingredients of the Ash Ill 

Non-metallic Elements 112 

Carbon and its Compounds 113 

Sulphur " " " 114 

Phosphorus" " " 117 

Silicon " " " 119 

Metallic Elements 123 

Potassium and its Compounds 124 

Sodium " " " 124 

Calcium " " " 125 

Magnesium and its Compounds 126 

Iron " " " 127 

Manganese " " " 128 

Salts 129 

Carbonates 130 

Sulphates 132 

Phosphates laS 

Chlorides 135 

Nitrates 136 

§ 2. Quantity, Distribution, and Variations of the Ash 138 

Table of Proportions of Ash in Vegetable Matter 139 

§ 3. Special Composition of the Ash of Agricultural Plants 147 

1. Constant Ingredients .148 

2. Uniform composition of normal specim's of given plant.148 
Table of Ash-analyses 150 

3. Composition of Diflerent parts of Plant 157 

4. Like composition of similar plants 159 

5. Variability of ash of same ^ecies 160 

0. What is normal composition of the ash of a plant ? 163 

7. To what extent is each ash-ingredient essential or acci- 

dental 166 

Water-culture 167 

Essential ash-ingredients 172 

Is Soda Essential to Agricultural Plants ? 172 

Oxide of Iron indispensable 178 

Oxide of Manganese unessential 179 

Is chlorine indispensable ? 180 

Silica is not essential 183 

Ash-ingredients taken up in excess 187 

Disposition of superfluous matters 189 

State of Ash-ingredients in plant 193 

§ 4. Functions of the Ash-ingredients 196 

Chap, m.— § 1. Quantitative Relations among the Ingredients of Plants 201 

§ 2. Composition of the plant in successive stages of growth 203 

Composition and Growth of the Oat Plant 2U4 

DIVISION II.— THE STRUCTURE OF THE PLANT AND OFFICES OF 
ITS ORGANS. 

Chap. I.— Generalities 220 

Organism, Organs 221 

8 



TABLE OF CONTENTS. IX 

Chap, n.— Pkimart Elements or Okganic Steucttjee 222 

§ 1. The Vegetable Cell 222 

I 2. Vegetable Tissues 232 

Chap, m.— Vegetative Organs 2a4: 

§1. The Root 234 

Spongioles. Root Cap 235 

Offices of Root 238 

Delicacy of Structure 239 

Apparent Search for Food 241 

Root-hairs. 243 

Contact of Roots with Soil 245 

Absorption by Root 248 

Soil Roots, Water Roots, Air Roots 252 

Excretions 258 

§ 2. The Stem 260 

Buds 261 

Layers, Tillering 264 

Root-Stocks 265 

Tubers 266 

Structure of the Stem 26t 

Endogenous Plants 268 

Exogenous " 273 

Sieve-cells 280 

§ 3. Leaves 283 

Leaf Pores 285 

Exhalation of Water Vapor 287 

Offices of Foliage. . . , 290 

Chap. IV.— Reproductive Organs 291 

§1. The Flower 291 

Fertilization 294 

Hybridizing 295 

Darwin's Hypothesis 298 

§ 2. Fruit 300 

Seed 302 

Endosperm 302 

Embryo 302 

• § 3. Vitalitv of seeds and their influence on the Plants they produce.305 

Duration of Vitality. 305 

Use of old. unripe and light seeds 307 

Church's Experiments on Seed Wheat 308 

DIVISION in.-LIFE OF THE PLANT. 

Chap. I.— Germination 310 

' § 1. Introductorj' 310 

§ 2. Phenomena of Germination 311 

§ 3. Conditions of Germination 312 

Proper Depth of Sowing .316 

§ 4. Chemical Physiology of Germination 318 

Chemistry of Malt 319 

Chap. IL— § 1. Food of the Plant when independent of the Seed 327 

I 2. The Juices of the Plant. Their Nature and Movements 330 

Flow of Sap., 331 

Bleeding 332 

Composition of Sap 337 

Kinds of Sap 338 

Motion of Nutrient Matters 340 

§ 3. Causes of Motion of the Juices 340 

Porosity of Tissues 340 

, Imbibition 346 

Capillary Attraction 349 

Liquid Diftusion 351 

Osmose or Membrane Diffusion 354 

Root Action 360 

Selective Power of Plant 362 

§ 4. Mechanical Effects of Osmose 36S 

I 5, Direction of Vegetable Growth 3® 

APPENDIX.— TABLES. 
Table I.-'Composition of the Ash of Agriculf 1 Plants and Product^; Averages.376 

1* 



HOW CEOPS GEOW. 



Table 
Table 
Table 
Table 
Table 
Table 
Table 
Table 
Table 
Table 

Table 



n.— Composition of Fresh or Air-dry Agricult'l Products in 1,000 parts..381 

III.— Proximate Composition of Agricultural Plants and Products 385 

IV.— Detailed Analyses of Bread Grains 388 

v.— Detailed Analyses of Potatoes 389 

VI.— Detailed Analyses of Sugar Beets oW-J 

VII.— Composition of Fruits 390 

Vin.— Fruits arranged in tlie Order of their Content of Sugar 39.:5 

IX.— Fruits arranged in the Order of their Content of Free Acid 393 

X.— Fruits arranged according to proportions between Acid, Sugar, etc. .393 
Xi.— Fruits arranged according to the proportions between Water, 

Soluble Matters, etc 394 

XTL- Proportion of Oil in Seeds 3J4 



INDEX 



Absorption by the root. . . .239, 250, 251 
Access of air to interior of Plant. . .288 

Acids, Definition of 86 

" Test for 87 

Acid elements 113 

Adhesion 26, 349 

Agriculture, Art of IT 

Agricultural products, Composition 

in 1,000 parts 381 

Agricultural Science, Scope of. 24 

" Experiment-Stations of 

Germany 24 

Air-passages in plant 289 

Air-roots 252 

Akene 301 

Albumin 96 

Albuminoids, Characters and com- 
position 94 

Albuminoids in animal nutrition. . .104 

. " Diffusion of. 364 

" in oat-plant 211,215 

" Mutual relations of. ..103 
" Proportion of, in vege- 
table products 109 

Alburnum 282 

Alcohol from saw-dust 75 

Aleurone 105 

Algae 177,223 

Alkali-earths -125 

" " Function of... 197 

" Metals 125 

Alkali-metals 123 

Alkalies 86, 124 

" Test for 87 

" Function of 197 

Alkaloids 110 

Alum, decomposed by diffusion. . . 3154 

Alumina 129 

Alumimun 129 

Ammonia, Carbonate 49 

" in plants ..108 

" Salts of 137 

" " in plant 137 

Amyloids 55 

" Transformation of 78 

Anhydrous phosphoric acid. 117 

" silicic acid 120 

" sulphuric acid 115 

Anther 292 

Apatite 135 

Apple, Cells of 223 



Arabic acid 70 

Arabin 70 

Arendt, Estimation of sulphur and 

sulphuric acid 195 

Arendt, Study of oat-plant 204 

" Analysis of oat-plant 141 

Argol 88 

Arrow root 63 

Arsenic in plants 123, 196 

Art and Science 17 

Artificial fecundation 295 

Ash-Ingredients 112, 138 

Excess of. 187 

" " " how dis- 
posed of. 189 

Ash-Ingredients, Function of, in 

plant 196 

Ash-Ingredients, The indispensable.146 
" " State of, in plant. . .193 

Ash of plants 30, 111 

" " Analyses, Tables of.l50, 376 
" " Composition of, nor- 
mal 163 

Ash of plants, Composition of, va- 
riations in 157, 163 

Ash of oat-crop 212, 216 

" Proportions of. Tables 139, 145 

" " " variations in ... 143 

Asparagus, Ash-analyses 176 

Assimilation 325 

Atmosphere, Oflices of. 329 

Atoms 47 

Atomic weight . .47, 48 

Avenin 101 

Azote 39 

Bark 269, 275 

" Ash of 380 

Barley, Ash-analyses.. 150, 153, 160, 378 

" Proximate analyses 387 

" " '' detailed..388 

" Eoot-cap of. 236 

" Root-hairs of . . 244 

Barley-Sugar 73 

Baryta in plants 196 

Bases, Definition of 86 

Bassorin 71 

Bast-cells 270, 275 

Bast-Tissue 233 

Bayberry tallow 91 

Bean, Ash-analyses 152, 154, 379 

" Proximate analysis 381 



INDEX. 



XI 



Bean, Leaf, Section of 28o 

" Seed 304 

Beeswax ;'l 

g?j;'f^-::::::-::::::-:::::::::::33i 

Bicarbonate of potatili 130 

Bicarbonate of soda 131 

Biennial plants 251 

Bitartrate of potash v ' „o ^ 

Bleeding of vine 250, 333 

Blight 323 

Blood-fibrin 9« 

Bone-black 33 

Bone-phosphate 13a 

Bread grains, Detailed analyses... 3Sb 
Bretschneider, Study of oat-plant. .. 204 

Bromine. 119 

Brucite • 12T 

Buckwheat, Ash-analyses.... 152, 153 

.' 163, 378 

Buckwheat, Proximate analysis. . . .387 
li '' " de- 
tailed 388 

Buds, Structure of. 2bl 

" Development under pressure. 3fa8 

Bulbs 267 

Butyrin 90 

Cabbage, Section of stem, fig 5b 

Cartas senilis. Lime salt in 191 

Caesium 12^ 

" Action in oat 19o 

Catfein Ill 

Cafteotanic acid iiy 

Calcium 12» 

Callous 343 

Calyx 293 

Cambium .' .' .' 271, 272, 276, 280 

Cane sugar J* 

Capillary attraction 349 

Caramel '3 

Carbon, Properties of 31 

'• In ash 113 

Carbonates 130 

Carbonate of lime 131 

" "potash 130 

" "soda 131 

Carbonic acid 113 

" as food of plant 328 

" " in ash-analyses 149 

Carbonization •_• • ■ • • 33 

Carrot, Ash-analyses loo, 15b, 3U 

Casein Iw 

Cassava ...... »* 

Caulerpa prolifera, fig 33U 

Causes of directive power 3(1 

" " motion of juices 34b 

Caustic potash 124 

" soda 1-5 

Canto tree 1^3 

Cell-contents • ^^ 

" membrane, Thickening of 237 

" multiplication 231 

" Structure of. 234 

Cells, Forms of. 23b 

" Sizeof -200 

Cellular plants *^'^ 

" tissue ~-^^ 

Cellulose. • — •^'^ 



Cellulose, Composition 60 

*' Estimation 60 

" Group 55 

Test for 59 

" Quantity of, in plants 62 

Cerasin 71 

Cereals, Ash-analyses of.. .150, 378, 379 

Chaff 294 

" Ash of 378 

Chemical affinity 46 

" "• overcome by os- 
mose 364 

Chemical combination 46 

" decomposition 46 

Chemistry. 26 

Cherry gum 71 

Chlorhydric acid US 

Chlorides US, 13o 

Chloride of ammonium, decompos- 

ed by plant 171 

Chloride of Magnesium 118 

" "■ Potassium 135 

" " Sodium 136 

Chlorine 118 

" essential to crops ? . . . .180, 183 

" function in plant 199 

" in strand plants 183 

Chlorophyll 109, 285 

" requires iron 300 

Church, on specific gravity of seeds.308 

Circulation of sap 330 

Citric acid ^ 

Citrates 13o 

Classes ^^^ 

Classification 3J8 

Clover, Ash of. .37b 

" soluble and insoluble ash-in- 

gredients -. 194 

Clover, washed by rain 190 

Coagulation .- • 9o 

Cochineal tincture, test for acids and 

alkalies 87 

Colloids 3^2 

Combustion 3o 

Common Salt 13o 

Composite plants 300 

Concentration of plant-food 171 

Concretions in plant 190 

Coniferous plants • • 300 

Copper in plants 129, 19b 

Cork 276,277 

Corn-starch ^Jj3 

Corolla 292 

Cotton, ash-analyses lob 

" fiber, fig 56,237 

" seed cake. Analysis of..378, 382 

Cotyledon .268,303 

Crops, composition in 1,000 parts., .dbl. 

Coniferous plants 300, 304 

Crude cellulose • • • • ^0 

Cryptogams -i'^'i-: ff^ 

Crystalloid aleuroue 107 

Crystalloids • • • -302 

Crystals in plant 190, 103 

Cubic centimeter o8 

Culms 263 

Cyanides }\* 

Cyanogen , . . 



.114 



XII 



HOW CEOPS GROW. 



Cyanophyll 110 

Darvviu ou insect-fertilization 295 

" Hypotliesis of. 298 

Decimal system of weights 58 

Deflagration 136 

Definite Proportions, Law of 47 

Deliquescent 135 

Density of seeds 308 

Depth of sowing 316 

Dextrin 69 

Diastase 321 

Dicalcic phosphate 134 

Dicotyledonous seeds 303 

Diffusion of liquids 351 

Diffusion-rates 352 

Dioecious plants 294 

Direction of growth 370 

Disodic phosphate 134 

Double llowers . .293 

Drains stopped by roots 253 

Drupe 300 

Dry weather, Effect of, on plants. . .144 

Ducts 234, 272 

Dundonald's treatise on Ag. Chem- 
istry 20 

Elements of Matter 25 

Elm roots 254 

Embryo 302 

Emulsin 101 

Endogens. 238 

Endogenous plants 268, 303 

Endosmose 355 

Endosperm 302 

Epidermis 269 

of leaf. 285,287 

Equisetum 184 

Equivalent replacement of bases . . . 201 

Eremacausis 37 

Estimation of Albuminoids 108 

'' Cellulose 60 

" Fat 94 

" " Starch 66,76 

" " Sugar 76 

'• " Water 54 

Etherial oils 90 

Excretion of mineral matters from 

leaves 192 

Exci'etions from roots. 258 

Exhalation of water from foliage 

287, a32 

Exogenous plants 237, 273. 303 

Exogens .237 

Exosmose 355 

Experiment-Stations of Germany... 24 

Extension of roots 240 

Extractive Matters 320 

Exudation of ash-ingredients 189 

Eyes of potato 237 

Families 298 

Fatty acids 93 

Fats 89 

" converted into starch 318 

Fat in oat crop ;.211, 215 

" Proportions of, in Vegetal)le 

Products 94 

Ferments 337 

Fertilization 294 

Fiber GO 



Fiber in oat crop 210, 214 

Fibrin 98 

Field-beet, ash-analyses.... 155, 176, 377 

'' " prox. " 387 

Flax fiber, tig 56, 227 

Flesh fibrin 99 

Fleshy roots 251 

Flower 291 

Flow of sap 331 

Fluorine in plants 119, 195 

Fodder plants, Ash of 376 

Foliage, Offices of. 290 

" white in absence of iron. .199 

Food of Plant 327 

Force 25 

Forces 26 

Formative layer 224 

Formulas, Chemical 50 

Fructification 294 

Fructose 73 

Fruit 300 

Fruits, Ash of. 379 

" Composition of. 390 

Fruit sugar 73 

Fuchsia, fig. of flower 293 

Fungi 223 

Gases, how distributed throughout 

the plant 365 

Gallicacid 110 

Gallotanuic acid 110 

Gelatinous Silica. 122, 123 

Genus ; Genera 298 

Germ 302 

Germination 310 

" Conditions of 312 

" Chemic'l Physiology of.318 

" Phenomena of. 311 

" Temperature of 312 

Girdling 342, 343, 344 

Glass 121 

Glauber's Salt 132 

Gliadin 101 

Globulin 97 

Glucose 74 

Glucosides 77, 110 

Gluten 99 

Gluten-Casein 100 

Glycerin 93 

Gourd fruits 301 

Grains 301 

" Ash of. 150,378 

Grain 58 

Grape Sugar 74 

Grasses, ash-analyses 157, 376 

'' prox. " 385 

Gravitation, influence on growth 371 

Growth 231 

" of roots 235 

' ' Downward and upward 372 

Gum, Amount of, in plants 72 

Gum Arabic 70 

Gum Tragacanth 71, 79 

Gun Cotfou 58 

Gypsum 133 

Gyde, Exp. on root-excretion 259 

Haberlandt, ou vitality of seeds 306 

Ilaemotrlobin 97 

llallett''s pedigree Avbeat 144 



INDEX. 



xin 



Hallier, Exp's on absorption of pig- 
ments by plant 360 

Hazel leaves, loss by solution 190 

Heart-wood 282 

Heavy metals 127 

Henrici's Exp. with raspberry roots.254 

Herbaceous stems 282 

Honey-dew 76 

Hooibrenk, artificial fecundation. . .295 

Horse-chestnut, Ash-analyses of 159 

Hybrid, Hybridizing 295 

Hydrated phosphoric acid 117 

" silica 121 

" sulphuric acid 116 

Hydrate of lime 126 

" "magnesia 127 

" "potash 124 

" " soda 125 

Hydration of membranes 357 

Hydrochloric acid 118 

Hydrogen 39, 112 

'• in Germination 323 

Imbibition 346 

Imbibing power 347, 348 

Imbricated 262 

Introduction 17 

Inorganic matter 29 

Intercellular spaces 226 

Intei'nodes 262 

Inulin 68 

Iodine in plants 119, 196 

" Solution of. 59 

Iron 127 

" Function of. 199 

Isomerism 81 

Jerusalem Artichoke, Cell of 224 

Juices of the Plant 330 

Kernel 302 

Lactose ■. 78 

Latent buds 263 

Law^s Canaii,ensis^ Air-roots of — 257 

Laurin 90 

Layers 264 

Leached ashes 132 

Lead in plants 196 

Leaf-green 110 

" pores 285 

Leaves, Structure of. 283 

" office in nutrition 328 

" of trees, Ash of 379 

" under artificial pressure 369 

Legume 301 

Legumin 101 

Leguminous plants 302, 304 

Legumes, ash-analyses . . . 152, 157, 379 

" prox. " 387 

Leucophyll 110 

Levulose 73 

Liebig on small seeds 308 

" " relations between N and 

P2O5 202 

Light, effect on direction of growth.375 

" " "■ germination 314 

Light seeds. Plants from 307 

Lignin 57 

Lime 126 

" essential to vegetation 172 

Lime-water ,36, 126 



Linolein 90 

Liquid Diftusion 351 

Lithia, Lithium 125 

" in plants 195 

Litter, Ash of 378 

Londet, on vitality of seeds 306 

Madder crop 195 

Magazine, Root as 25 

Magnetic oxide of iron 128 

Magnesia 127 

" Movements of, in oat 219 

Magnesium 126 

Maize, ash-analyses 151, 153, 379 

" prox. " 387 

" paper 57 

" seed, Section of. 303 

" stalk, " " 268 

Maizena 63 

Malates 136 

Malate of lime 88 

Malic acid : 88. 89 

Malt, Chemistry of 319 

Maltose 75 

Manganese 128 

" cannot replace iron 201 

Manna 77 

Mannite ■ 78 

Maple, Flow of sap from 332 

" sugar 73 

Margarin 99 

Matter 25 

Meadow hay. Ash of. 376 

Medullary rays. 276 

Membrane-difiusion 354 

Membranes, Influence on motion 

of juices 365 

Metals 112 

Metallic elements 123 

Metapectic acid 83 

Metarabic acid 71 

Milk ducts 281 

Millon's test 96 

Moisture, in Germination 313 

Molecular Weights 48 

Molecules 48 

Monsecious plants 294 

Monocotyledonous seeds 303 

Monocalcic phosphate 134 

Motion caused by adhesion, 350 

Mould 223 

Mucidin 101, 321 

Multiple Proportions 48 

Mummy wheat 305 

Muriate of soda 136 

Muriatic acid 119 

Mustard, Root-hairs of. 244 

Mycose 78 

Myristin 90 

Nasturtium, Cells of. 227 

Nicotin 110 

Mter, nitrate of potash 136 

Nitrates in plants 108, 136 

Nitrocellulose 58 

Nitrogen, Properties of 37 

" in ash 112 

" " Germination 323 

" relation to phosphoric 
acid 203 



xrv 



HOW CKOPS GROW. 



Nobbe & Siegei't, Exp. on buck- 
wheat 188 

Nodes 2(J2 

Nomenclature, Botanical 299 

Nou-Metals 112 

Norton's analyses of oat-p]aut..l41, 204 

Notation, Chemical 49 

Nucleus 422, 278 

Nucleolus 224 

Nut SOO 

Nutrient matters in plant, Motion of.340 

Nutrition of seedling. . . 318 

" plant 327 

Oat. ash-analysis 151, 153, 157, 160 

' 101,102, 378 

" prox, " 378 

" " " detailed .388 

" crop, weight per acre 387 

" plant. Composition and growth 

of 204, 207, 214, 217 

Oat, proportions of ash in its differ- 
ent parts 141 

Oats, weight per bushel 102 

Offices of organs of plant 220 

Oil in seeds, etc 89, 90, 394 

" of nnistard 114 

" " vitriol 42, 116 

Oils, Properties of. 89 

Old seeds. Plants from 307 

Oleic acid 93 

Olein 90, 92 

Orders 298 

Organic matter 29 

Organism 221 

Organs 221 

Osmose 354 

" mechanical effects on plant.. 367 

Osmometer 355 

Ovaries 293 

Ovules 293 

Oxalates 136 

Oxalate of ammonia 86 

" " lime 85, 86 

" " " in walnut 191 

Oxalic acid 85 

Oxide of iron 000 

•' " " essential to plants 178 

'* " " State of, in plant 193 

" " manganese in ash ..179 

Oxides 37 

" of iron, described 127 

" " manganese, described... 128 

Oxygen, Properties of 33 

" occurrence in ash 113 

" in Assimilation 326 

" " Germination ■ 314 

Palmitic acid 93 

Palmilin 90, 92 

Parenchyma 233 

Papilionaceous plants 299 

Pappus 301 

Pea, ash-analysis 152, 153, 379 

" prox. " 387 

" ultimate analysis 45 

Pearlash 130 

Poetic acid , 82, 84 

Pectin 81 

Pectosicacid 82 



Pectose 81 

Pedigree wheat 144 

Permeability of cells 232 

Peroxide of iron 128 

Petals 292 

Phaenogams 299 

Phantom bouquets 57 

Phloridzin 77 

Phosphate of lime 134 

•' " soda 134 

" " potash 134 

Phosphates 43, 44, 117, 133 

" function in plants 197 

" relation to albuminoids. 202 

Phosphoric acid 38, 44, 117 

■•' " in oat-crop 218 

Phosphorite i:55 

Phosphorized oils 45, 92 

Phosphorus... 43,117 

"• in albuminoids 102 

" " fats of various plants. 92 

Physics 26 

Physiology 27 

Pinite 78 

Pistils 293 

Pith 269 

" rays 276 

Plastic Elements of Nutrition 104 

Plaster of Paris 133 

Plumule 303 

Pod ....301 

Pollarding 264 

Pollen... 293 

Polygonum convolvulus^ Fertilization 

of, fig 295 

Pome .301 

Porosity of vegetable tissues 346 

Potato, ash-analyses... 154, 162, 165, 877 

" prox. analyses 387 

" " " detailed 389 

" ultimate" 45 

' ' leaf. Pores of, fig 286 

' ' stem. Section of, fig 281 

" sugar 74 

" tuber. Structure and Section 

of, fig 274,277 

Potato tuber, why mealy 226 

Potash 124, 130 

" lye 124 

" in strand and marine plants. .178 

Potassium 124 

Chloride of 135 

Prosenchyma 232 

Protagon 93 

Protoplasm 224 

Protein bodies 94, 103 

Protoxide of iron 127 

" " manganese 128 

Proximate Composition of Crops... 385 

". Elements 153 

Prussic Acid 114 

Puft'-balls 232 

Pulp of fruits 223 

Quack grass 266 

Quantitative relations among ingre- 
dients of plant 201 

Quartz 130 

Quercitauuic acid 110 



IKDEX. 



XV 



Quercite "78 

Radicle 303 

Red clover hay, Ultimate analysis of. 45 

'' beet, Pigment of 367 

" pine, Pith rays of 276 

" snow 223 

Relations of Cellulose and Pectose 

Groups 84 

Relations of Fats to Amyloids 94 

" " Veg. Acids to Amy- 
loids 89 

Reproductive Organs 222, 291 

Rice, ash-analysis 151, 152, 379 

" pros. '• 387 

" " " detailed 389 

" roots of 252 

Rind 275 

Ringing of stems 341 

Rock Crystal 120 

Root-action, imitated 361 

" " in winter 333 

" " Osmose in 360 

" cap 2;d5 

" crops, ash-analyses 155, 377 

" '^ prox. " 387,389 

" cuttings 237 

" distin^^uished from stem 236 

" excretions 258 

" hairs 243 

" office in Nutrition 327 

" power of vine 248 

" Seat of absorptive force in 249 

" stock 265 

Rootlets 238 

Roots, Structure of. 234 

" Bursting of 369 

" contact with soil 245 

" going down for water 254 

" Search of food hy 241 

" Quantity of 242 

Rubidium 125 

'• action on oat 196 

Runners 264 

Rye, ash-analysis 150, 153, 379 

'' prox. " 387,388 

Saccharose 72 

'•'• Amount of, in plants 73 

Sago 64 

SalaeratUB 131 

Salicin 77 

Salicornia 117, 177 

Salm-Horstmar, Exp's in artificial 

soils 166 

Sal-soda 131 

Salsola 177,183 

Salts, Definition of 86 

" in ash of plants 129 

" Properties of. 87 

Saltwort 177 

Samphire 177 

Sap 330 

" Acid and alkaline 366 

" ascending 340 

" descending 341 

" Composition of .337 

" of sunflower , 338 

" Springflowof 334 

" wood 283 



Saponification 93 

Saussure, exp. on mint 187 

Saxifraga crustata 192 

Scotch fir. Wood-cells of, fig 279 

Scouring rush ...184 

Screw pine, Root cap of, fig 236 

Sea-weeds, Potash in, . 198 

Seed ; ., 302 

" vessel HOO 

Seeds, constancy of composition. ..145 

Selecting power of plant 329, 362 

Seoals ....292 

Series 298 

Sesquioxide of iron 128 

" " manganese 128 

Sieve-cells 280 

" in pith 313,345 

Silex 120 

Silica 120 

" does not prevent lodging of 

grain 198 

" Function of, in plant 197 

" in ash 183 

" "oat 198 

" " textile materials 185 

" unessential to plants 183 

Silicates 120 

Silicate of potash 120 

Silicic acid 120 

Silicon 119 

Silk of maize 294 

Silver Fir, Roots of 245 

Silver-grain ... 276 

Skeletonized plants 57 

Soaps 93 

Soda... 125 

" can it replace potash ? 176 

" essential to ag. plants ? 172 

" in strand and marine plants. . . 177 
" Variations of, in field-crops. . .173 

Soda-ash 131 

Sodium 124 

Chloride of ..136 

Sorghum sugar 73 

Soli, Ofiices of 329 

Soil-roots 252 

Solution of starch in Germination.. 322 

' • for water-culture 168 

Soluble silica 121 

" starch 322 

Species 29(5 

Spirits of salt 119 

Spongioles 235 

Stamens 292 

Starch, amount in plants 66 

" estimation 66 

" in wood, 337 

" Properties of. 63 

" sugar 74 

" Test for 64 

" unorganized 64 

Stearic acid 93 

Stearin 90,92 

Stem, Endogenous 269 

" Exogenous 273 

" Structure of. 267 

Stems 261 

Stigma 293 



XVI 



HOW CEOPS GROW. 



Stomata 285 

Stool 265 

Straw, asli-analyses 152, 153, 157 

'' piox. " 386 

Structtire of plant 220 

Suckers 266 

Sugar-beet, ash-analyses 154, 156,158 

" "• detailed analyses 389 

Sugar, estimation of. 76 

" in cereals 77 

" " sap 338 

" of milk 78 

" Trommer's test for 75 

Sulphate of lime 133 

" potash 132 

" " Boda ...132 

Sulphates 43, 117, 132 

" Function of. 196 

" in clover 194 

" reduced by plant 190 

Sulphides 42 

Sulphide of potassium 115 

Sulphites 115 

Sulphocyanide of allyle 114 

Sulphur 42, 114 

" in oats 194 

Sulphureted hydrogen 43, 115 

Sulphurets 42 

Sulphuric acid .42, 116 

" in oat 219 

Sulphurous acid 42, 115 

Sulphydric acid 43, 115 

Supercarbonate of soda 131 

Superphosphate of lime 135 

Symbols, Chemical 47 

Tabashir 183 

Tannin 77, 110 

Tao-foo 101 

Tapioca 64 

Tap-roots 237 

Tartaric acid 88, 89 

Tartrates 136 

Tassels of maize 294 

Teak, Phosphate of lime in 191 

Tensicm in plant 372 

Tests for albuminoids 96 

Textile plants. Ash of 378 

Theobromin Ill 

Thlaspi, var. calaminai'is 196 

Tillering 265 

Titanic acid 123, 195 

Titanium 123 

Tobacco, ash-analyses 378 

" Silica in 185 

Touch-paper 136 

T'radescantia zebrina^ Air-roots of. .257 
Transformations of cell-contents. ..229 
Translocation of substances in 

plant.. 218 

Transplanting 255 

Tricalcic phosphate 134, 135 

Tubers 260 

Turnip, ash-analyses 155, 156, 377 

prox. •• 387 

Tuscan hat-wheat 144 

Ultimate Composition of Vegetable 

Matters 45 

Umbelliferous plants 207 



Unripe seed, Plants from 300 

Variation of ash-ingredients, limit- 
ed 147, 148 

Varieties 297 

" Causes of .144 

Vascular bundle of maize stalk 270 

Vascular-Tissue. . , 233 

Vegetable acids 85 

" albumin 97 

" casein; 100 

cell 222 

fibrin 99 

" ivory 226 

" mucilage 71 

" parchment 58 

" tissue 22.5,232 

Vegetative organs 222, 234 

Veins of the leaf 285 

Vine, Bleeding of 332 

Viola calaminaris. 196 

Vitality of roots 260 

'' " seeds 305 

Vital Principle 221 

Water,Composition of. 53 

" Estimation of 55 

" Formation of 41 

" imbibed by roots 248 

" " " seeds 360 

" in air-dry plants 55 

" " fresh plants 54 

" of plant atfected by soil .369 

" " vegetation. Free 55 

" " " Hygroscopic. 55 

Water-bath 54 

Water-culture 167 

Water-glass 120 

Water Roots 252, 253 

Wax 89,90 

'" in oat-plant 211 

Well-water, used in water-culture, 

Composition of 171 

Wheat, ash-analyses 150, 152, 379 

" prox. " 387 

" detailed 388 

" ultimate analyses 45 

" gum 99 

" straw, proximate analysis. . . 886 
" "■ ultimate '' ... 45 

" roots of. 246, 247 

White of Q^g 96 

Wiegmann & Polstroff, Exp. with 

cress 146 

Wilting 334 

Wolff, Exp. Avith buckwheat 164 

Wood 57 

." Amount of water in 333 

" Ash of 379 

" cells 271 

" " of conifers 279 

" paper 57 

Woody-liber 60 

" stems 282 

" tissue •. 233 

Yeast 223, 231 

Zamia spiralis, Root of. 252 

Zanthophyll 110 

Ziuc ..129, 131 



H0¥ CROPS GRO¥. 



INTRODUCTIOI^. 



The objects of agriculture are the produdion of certain 
plants and certain animals which are employed to feed and 
clothe the human race. The first aim, in all cases, is the 
production of plants. 

Nature has made the most extensive provision for the 
spontaneous growth of an immense variety of vegetation ; 
but in those climates where civilization most certainly at- 
tains its fullest development, man is obliged to employ art 
to provide himself with the kinds and quantities of vege- 
table produce which his necessities or luxuries demand. 
In this defect, or, rather, neglect of nature, agriculture has 
its origin. 

The art of agriculture consists in certain practices and 
operations which have gradually grown out of an obser- 
vation and imitation of the best efforts of nature, or have 
been hit upon accidentally. 

The science of agriculture is the rational theory and ex- 
position of the successful art. 

Strictly considered, the art and science of agriculture 
are of equal age, and have grown together from the ear- 
liest times. Those who first cultivated the soil by dig- 
17 



18 HOW CHOPS GEOW. 

ging, planting, manuring, and irrigating, had their suffi- 
cient reason for every 'step. In all cases, thought goes 
before work, and the intelligent workman always has a 
theory upon which his practice is planned. ]S"o farm 
was ever conducted without physiology, chemistry, and 
physics, any more than an aqueduct or a railway was ever 
built Avithout mathematics and mechanics. Every success- 
ful farmer is, to some extent, a scientific man. Let him 
throw away the knowledge of facts and the knowledge of 
princijDles which constitute his science, and he has lost the 
elements of his success. The farmer without his reasons, 
his theory, his science, can have no plan ; and these want- 
ing, agriculture would be as complete a failure with hi-m 
as it would be with a man of mere science, destitute of 
manual, financial, and executive skill. 

Other qualifications being equal, the more advanced and 
complete the theory of which the farmer is the master, the 
more successful must be bis farming. The more he knows, 
the more he can do. The more deeply, comprehensively, 
and clearly he can thhik^ the more economically and ad- 
vantageously can he work. 

That there is any opposition or conflict between science 
and art, between theory and practice, is a delusive error. 
They are, as they ever have been and ever must be, in the 
fullest harmony. If they appear to jar or stand in con- 
tradiction, it is because we have something false or incom- 
plete in what we call our science or our art ; or else we do not 
perceive correctly, but are misled by the narrowness and 
aberrations of our vision. It is often said of a machine, 
that it was good in theory, but failed in practice. This is 
as untrue as untrue can be. If a machine has failed in 
practice, it is because it was imperfect in theory. It should 
be said of such a failure — the machine was good, judged 
by the best theory known to its inventor, but its incapacity 
to work demonstrates that the theory had a flaw. 

But, although art and science are thus inseparable, it 



INTEODTJCTIO^q-. 19 

must not be forgotten that their growth is not altogether 
parallel. There are facts in art for which science can, as 
yet, furnish no adequate explanation. Art, though no 
older than science, grew at first more rapidly in vigor and 
in stature. Agriculture was practised hundreds and 
thousands of years ago, with a success that does not com- 
pare unfavorably with ours. I^early all the essential points 
of modern cultivation were regarded by the Romans be- 
fore the Christian era. The annals of the Chinese show 
that their wonderful skill and knowledge were in use at a 
vastly earlier date. 

So much of science as can be attained through man's 
unaided senses, reached considerable perfection early in 
the world's history. ' But that part of science which re- 
lates to things invisible to the unassisted eye, could not 
be developed until the telescope and the microscope had 
been invented, until the increasing experience of man and 
his improved art had created and made cheap the other in- 
ventions by whose aid the mind can penetrate the veil of 
nature. Art, guided at first by a very crude and imperfectly 
developed science, has, within a comparatively recent pe- 
riod, multiplied those instruments and means of research 
whereby science has expanded to her present proj^ortions. 

The progress of agriculture is the joint w^ork of theory 
and practice. In many departments great advances have 
been made during the last hundred years ; especially is this 
true in all that relates to implements and machines, and to 
the improvement of domestic animals. It is, however, in 
just these departments that an improved theory has had 
sway. More recent is the development of agriculture in its 
chemical and physiological aspects. In these directions the 
present century, or we might almost say the last 30 years, 
has seen more accomplished than all previous time. 

The first book in the English language on the subjects 
which occupy a good part of the following pages, was 
written by a Scotch nobleman, the Earl of Dundonald, and 



23 HOW CEOPS GKOW. 

was published at London in 1795. It was entitled : " A 
Treatise showing the Intimate Connection that subsists 
between Agriculture and Chemistry." The learned Earl 
in his Introduction remarked that " the slow progress 
which agriculture has hitherto made as a science is to be 
ascribed to a want of education on the part of the culti- 
vators of tlie soil, and the want of knowledge in such au- 
thors as have written on agriculture, of the intimate con- 
nection that subsists between the science and that of 
chemistry. Indeed, there is no operation or process, not 
merely mechanical, that does not depend on chemistry, 
which is defined to be a knowledge of the properties of 
bodies, and of the effects resulting from their different 
combinations." Earl Dundonald could not fail to see that 
chemistry was ere long to open a splendid future for the 
ancient art that always had been and always is to be the 
prime support of the nations. But when he wrote, no 
longer than seventy-two years ago, how feeble was the 
light that chemistry could throw upon the fundamental 
questions of agricultural science ! The chemical nature of 
atmospheric air was then a discovery of barely 20 years' 
standing. The composition of water had been known but 
12 years. The only account of the composition of plants 
that Earl Dundonald could give, was the following: 
*' Vegetables consist of mucilaginous matter, resinous 
matter, matter analogous to that of animals, and some pro- 
portion of oil. * * Besides these, vegetables contain 
earthy . matters, formerly held in solution in the newly 
taken-in juices of the growing vegetable." To be sure he 
explains by mentioning on subsequent pages that starch 
belongs to the mucilaginous matters, and that, on analysis 
by fire, vegetables yield soluble alkaline salts and insolu- 
ble phosphate of lime. But these salts, he held, were 
formed in the process of burning, their lime excepted, and 
the fact of their beins^ taken from the soil and constitutinsc 
the indispensable food of plants, his Lordship was unac- 



INTEODTTCTION^. 21 

quainted with. The gist of agricultural chemistry with 
him was, that plants are " composed of gases with a small 
proportion of calcareous matter ; " for " although this 
discovery may appear to be of small moment to the prac- 
tical farmer, yet it is well deserving of his attention and 
notice, as it throws great light on the nature and food of 
vegetables." The fact being then known that plants ab- 
sorb carbonic acid from the air, and employ its carbon in 
their growth, the theory was held that fertilizers operate 
by promoting the conversion of the organic matter of the 
soil or of composts into gases, or into soluble humus, 
which were considered to be the food of plants. 

The first accurate analysis of a vegetable substance was 
not accomplished until 15 years after the publication of 
Dundonald's Treatise, and another like period passed be- 
fore the means of rapidly multiplying good analyses had 
been worked out by Liebig. So late as 1838, the Gottingen 
Academy offered a prize for a satisfactory solution of the 
then vexed question whether the ingredients of ashes are 
essential to vegetable growth. It is, in fact, during the last 
30 years that agricultural chemistry has come to rest on 
sure foundations. Our knowledge of the structure and 
physiology of plants is of like recent development. 
What immense practical benefit the farmer has gathered 
from this advance of science ! The dense populations of 
Great Britain, Belgium, Holland, and Saxony, can attest 
the fact. Chemistry has ascertained what vegetation ab- 
solutely demands for its growth, and points out a multitude 
of sources whence the requisite materials for crops can be 
derived. To be sure, Cato and Columella knew that ashes, 
bones, bird-dung and green manuring, as well as drain- 
age and aeration of the soil, were good for crops ; but 
that carbonic acid, potash, phosphate of lime, and com- 
pounds of nitrogen, are the chief pabulum of vegetation, 
they did not know. They did not know that the atmos- 
phere dissolves the rocks, and converts inert stone into 



22 HOW CROPS GROW. 

nutritive soil. These grand principles, understood in many 
of their details, are an inestimable boon to agriculture, 
and intelligent farmers have not been slow to apply them 
in practice. The vast trade in phosphatlc and Peruvian 
guano, and in nitrate of soda ; the great manufactures of 
oil of vitriol, of superphosphate of lime, of fish fertilizers ; 
and the mining of fossil bones and of potash salts, are 
largely or entirely industries based upon and controlled 
by chemistry in the service of agriculture. 

Every day is now the witness of new advances. The 
means of investigation, which, in the hands of the scien- 
tific experimenter, have created within the writer's mem- 
ory such arts as photography and electro-metallurgy, and 
have produced the steam engine and magnetic telegraph, 
are working and shall continue to work progress in agri- 
culture. This improvement will not consist so much in 
any remarkable discoveries that shall enable us " to grow 
two blades of grass where but one grew before," but in 
the gradual disclosure of the reasons of that which we 
have long known, or believed we knew, in the clear sepa- 
ration of the true from the seemingly true, and in the ex- 
change of a wearying uncertainty for settled and positive 
knowledge. 

It is the boast of some who affect to glory in the suf- 
ficiency of practice and decry theory, that the former is 
based upon experience, which is the only safe guide. But 
this is a one-sided view of the matter. Theory is also 
based upon experience, if it be truly scientific. The vaga- 
rizing of an ignorant and undisciplined mind is not theory. 
Theory, in the good and proper sense, is always a deduc- 
tion from facts, the best deduction of which the stock of 
facts in our possession admits. It is the interpretation of 
facts. It is the expression of the ideas which facts awaken 
when submitted to a fertile imagination and well-balanced 
judgment. A scientific theory is intended for the nearest 
possible approach to the truth. Theory is confessedly im- 



INTEODUCTION". 23 

perfect, because our knowledge of facts is incomplete, our 
mental insiglit weak, and our judgment fallible. But the 
scientific theory which is framed by the contributions of a 
multitude of earnest thinkers and workers, among whom 
are likely to be the most gifted intellects and most skillful 
hands, is, in these days, to a great extent worthy of the 
Divine truth in nature, of which it is the completest hu- 
man conception and expression. 

Science employs, in effecting its progress, essentially the 
same methods that are used by merely practical men. 
Its success is commonly more rapid and brilliant, because 
its instruments of observation are finer and more skillfully 
handled ; because it experiments more industriously and 
variedly, thus commanding a wider and more fruitful ex- 
perience ; because it usually brings a more cultivated im- 
agination and a more disciplined judgment to bear upon 
its work. The devotion of a life to discovery or invention 
is sure to yield greater results than a desultory applica- 
tion made in the intervals of other absorbing pursuits. It 
is then for the interest of the farmer to avail himself of 
the labors of the man of science, when the latter is willinor 
to inform himself in the details of practice, so as rightly 
to comprehend the questions which press for a solution. , 

It is characteristic of our time that large associations of practical 
agriculturists have recognized the immediate pecuniary advantage to he 
derived from the application of science to their art. This was first done 
at Edinburgh, in 1843, by the establishment of the "Agricultural Chem- 
istry Association of Scotland." 

This organization limited itself to a duration of five years. At the 
expiration of that time, its labors, v^^hich had been ably conducted by 
Prof. James F. W. Johnston, were assumed by the Highland and Agri- 
cultural Society of Scotland, and have been prosecuted up to the present 
day by Dr. Anderson. The Eoyal Ag'l Soc. of England began to employ a 
consulting chemist, Dr. Lyon Playfair, in 1843; and since 1848 most 
valuable investigations, by Prof. Way and Dr. Voelcker, have regularly 
appeared in its journal. Other British Ag'l Societies have followed these 
examples with more or less effect. 

It is, however, in Germany that the most extensive and well-organized 
efforts have been made by associations of agriculturists to help their 



24 HOW CROPS GEOW. 

practice by developing theory. la 1851 the Agricultural Society of Leip- 
zig, {Leipziger Oeconomische Societcet), established au Ag''l Experiment 
Statiwi on its farm at Moeckern, near that city. Tbis example was soon 
imitated in other parts of Germany and the neighboring countries ; and 
at the present writing, 1867, there are of similar Experiment Stations in 
operation — in Prussia 10, in Saxony 4, in Bavaria 3, in Austria 3, in 
Brunswick, Hesse, Thuringia, Anhalt, Wirtemberg, Baden, and Sweden, 1 
each, making a total of 26, chiefly sustained by, and operating in, the in- 
terest of the agriculturists of those countries. These stations give con- 
stant employment to 60 chemists and vegetable physiologists, of whom 
a large number are occupied largely or exclusively with theoretical iur 
vestigations, while the work of others is devoted to more practical mat- 
ters, as testing the value of commercial fertilizers. Since 1859 a journal, 
Bie Lmiclwirthschaftlichen Versuchs-Stationen, (As;'! Exp. Stations), has 
been published as the organ of these establishments, and the 9 volumes 
now completed, together with the numerous Reports of the Stations 
themselves, have largely contributed the facts that are made use of in 
the following pages. 

In this country some similar enterprises have been attempted, but 
have not been supported with a sufl3.cient combination of talent and pe- 
cuniary outlay to ensure any striking success in the direction of agri- 
cultural chemistry. An imitation of the example set by European as- 
sociations is well worthy the consideration of our State Ag'l Societies, 
many of which could easily command the funds for such an enterprise. 
It would be found that such a use of their resources would siDeedily 
strengthen their hold on the interest and regard of the communities 
they represent. 

Agricultural science, in its widest scope, comprehends a 
vast range of subjects. It includes something from nearly 
every department of human learning. 

The natural sciences of geology, meteorology, mechan- 
ics, physics, chemistry, botany, zoology and physiology, 
are most intimately related to it. It is not less concerned 
with social and political economy, with commerce and 
law. In the treatises of which this is the first, it will not 
be attempted to cover nearly all this ground, but some 
account will be given of certain sabjects whose under- 
standing promises to be of the most direct service to the 
agriculturist. The theory of agriculture, as founded on 
chemical, physical, and physiological science, is the topic 
of this and the succeedinor volume. 



INTEODTJCTION. 25 

Some preliminary propositions and definitions may be 
serviceable to the reader. 

Science deals with matter and force. 

Matter is that which has weight and bulk. 

Force is the cause of changes in matter — ^it is appre- 
ciable only by its effects upon matter. 

Force resides in and is inseparable from matter. 

Force manifests itself in motion. 

All matter is perpetually animated by force — ^is there- 
fore never at rest. What we call rest in matter is simply 
motion too fine for our perceptions. 

The different kinds of matter known to science have 
been resolved into not more than 62 elements or simple 
substances. 

Elements, or ultimate elements, are forms of matter 
which have thus far resisted all attempts at their simplifi- 
cation. 

In ordinary life we commonly encounter but 12 elements 
in their elementary state, viz. : 

Oxygen, Mercury, 

Nitrogen, Copper, 

Sulphur, Lead, 

Carbon, Tin, 

Iron, Silver, 

Zinc, Gold. 

The numberless other substances with which we are 
familiar, are mostly compounds of the above, or of 12 
other elements, viz. : 

Hydrogen, Calcium, 

Phosphorus, Magnesium, 

Chlorine, Aluminum, 

Silicon, Manganese, 

Potassium, Chromium, 

Sodium, Nickel. 
^2 



26 



HOW CEOPS GEOW. 



"We distinguish a number of forces, wliicli, acting on or 
through matter, produce all material phenomena. In the 
subjoined scheme the recognized forces are to some ex- 
tent classified and defined, in a manner that may prove 
useful to the reader. 

r 



Act at sensi 
ble and in- 
sensible 
distances 



Act only at 
insensible 
distances 



Kepulsive 
Attractive 

and 
Eepulsive 



LIGHT 
HEAT 

ELECTRICITY 

Magnetism 

GRAVITATION 
COHESION 
Crystallization 
Attractive^ ADHESION 
Solution 
Osmose 
AFFINITY 
VITALITY 



Radiant 

Inductive 
Cosmieal 



■Molecular 



Atomic 
Organic 



■ Physical 



Chemical 
Physiological 



The sciences that more immediately relate to agricul- 
ture are : 

I* — Physics or natural philosophy, — the science which 
considers the general properties of matter and such of its 
phenomena as are not accompanied by essential change 
in its obvious qualities. All the forces in the preceding 
scheme, save the last two, manifest themselves through 
matter without destroying or masking the matter itself. 
Iron may be hot, luminous, or magnetic, may fall to the 
ground, be melted, welded, and crystallized ; but it remains 
iron, and is at once recognized as such. The forces whose 
play does not disturb the evident characters of substances 
are physical. 

II« — Chemistry J — the science which studies the proper- 
ties peculiar to the various kinds of matter, and those 
phenomena which are accompanied by a fundamental 
change in the matter acted on. Iron rusts, wood burns, 
and both lose all the external characters that serve for 
their identification. They are, in fact, converted into other 
substances. Affinity, or chemical affinity, unites two or 
more elements into compounds, unites compounds together 
into more complex compounds; and, under the influence of 



INTRODUCTIONS. 27 

heat, light, and other agencies, is annulled or overcome, so 
that compounds resolve themselves into simpler combina- 
tions or into their elements. Chemistry is the science of 
composition and decomposition ; it considers the laws and 
results of affinity. 

Ill, — ^Physiology, which unfolds the laws of the devel- 
opment, sustenance, and death, of living organisms. 

When we assert that the object of agriculture is to de- 
velop from the soil the greatest possible amount of cer- 
tain kinds of vegetable and animal produce at the least 
cost, we suggest the topics which are most important for 
the agriculturist to understand. 

The farmer deals with the plant, with the soil, with ma- 
nures. These stand in close relations to each other, and 
to the atmosphere which constantly surrounds and acts 
upon them. How the plant grows, — the conditions under 
which it flourishes or suffers detriment, — the materials 
of which it is made, — the mode of its construction and 
organization, — how it feeds upon the soil and air, — how it 
serves as food to animals, — ^how the air, soil, plant, and 
animal, stand related to each other in a perpetual round 
of the most beautiful and wonderful transformations, — 
these are some of the grand questions that come before 
us ; and they are not less interesting to the philosopher 
or man of culture, than important to the farmer who 
depends upon their practical solution for his comfort ; or 
to the statesman, who regards them in their bearings 
upon the weightiest of political considerations. 



DIVISION I. 

CHEMICAL COMPOSITION OF THE PLANT. 

CHAPTER L 
THE VOLATILE PAET OF PLANTS. 

§1. 

DISTINCTIONS AND DEFINITIONS. 

Okganic and Inoegais-ic Mattee. — ^All matter may be 
divided into two great classes — Organic and Inorganic. 

Organic matter is the product of growth, or of vital 
organization, whether vegetable or animal. It is mostly 
combustible, i. e., it may be easily set on fire, and burns 
away into invisible gases. Organic matter either itself 
constitutes the organs of life and growth, and has a pecu- 
liar organized structure, inimitable by art, — is made up of 
cells, tubes or fibres, (wood and flesh) ; or else is a mere 
result or product of the vital processes, and destitute of 
this structure (sugar and fat). 

All matter which is not a part or product of a living 
organism is inorganic or mineral matter (rocks, soils, wa- 
ter, and air). Most of the naturally occurring forms of 
inorganic matter which directly concern agricultural chem- 
istry are incombustible, and destitute of anything like or- 
ganic structure. 

By the processes of combustion and decay, organic mat- 
ter is disorganized or converted into inorganic matter, 
while, on the contrary, by vegetable growth inorganic 
matter is organized, and becomes organic. 
29 



30 HOW CROPS GROW. 

Organic matters are in general characterized by com- 
plexity of constitution, and are exceedingly numerous and 
various ; while inorganic bodies are of simpler composi- 
tion, and comj)aratively few in number. 

Volatile and Fixed Mattee. — ^All j^lants and animals, 
taken as a whole, and all of their organs, consist of a vola- 
tile and a fixed part, which may be separated by burning ; 
the former — ^usually by far the larger share — ^passing into, 
and mingling with the air as invisible gases ; the latter — 
forming, in general, but from one to five • per cent of the 
whole — remaining as ashes. 

Experiment 1.— A splinter of wood heated in the flame of a lamp 
takes fire, burns, and yields volatile matter^ which consumes with flame, 
and ashes^ which are the only visible residue of the combustion. 

Many organic bodies, products of life, but not essential 
vital organs, as sugar, citric acid, etc., are completely 
volatile when in a state of purity, and leave no ash. 

CuERENT Use of the Teems Oeganic and Inorgan- 
ic. — It is usual among agricultural writers to confine the 
term organic to the volatile or destructible portion of vege- 
table and animal bodies, and to designate their ash-ingre- 
dients as inorganic tnatter. This use of the words is ex- 
tremely inaccurate. What is found in the ashes of a tree 
or of a seed, in so far as it was an essential j^art of the or- 
ganism, was as truly organic as the volatile portion, and by 
submitting organic bodies to fire, they may be entirely 
converted into inorganic i^atter, the volatile as well as the 
fixed parts. 

Ultimate Elements that Constitute the Plant. — 
Chemistry has demonstated that the volatile and destruct- 
ible part of organic bodies is made up chiefly of four sub- 
stancies, viz. : carbon, oxygen, hydrogen, and nitrogen, 
and contains two other elements in lesser quantity, viz. : 
sulphur and phosphorus. In the ash we may find phos- 
phorus, sulphur, sihcon, chlorine, potassium, sodium, cal- 



THE VOLATILE PABT OF PLAINTS. 31 

cium, magnesium, iron, and manganese, as well as oxygen, 
carbon, and nitrogen.* 

These fourteen bodies are elements^ which means in 
chemical language, that they cannot be resolved into other 
substances. All the varieties of vegetable and animal 
matter are compounds^ — are composed of and may be re- 
solved into these elements. 

The above fourteen elements being essential to the or- 
ganism of every plant and animal, it is of the highest im- 
portance to make a minute study of their properties. 

ELEMENTS OF THE VOLATILE PART OF PLANTS. 

For the sake of convenience we shall first consider the 
elements which constitute the destructible part of plants, 
viz. : 

Carbon, Hydrogen, 

Oxygen, Sulphur, 

Nitrogen, Phosphorus. 

The elements which belong exclusively to the ash will 
be noticed in a subsequent chapter. 

Carbon; in the free state, is a solid. We are familiar 
with it in several forms, as lamp-black, charcoal, anthracite 
coal, black-lead, and diamond. IsTot withstanding the 
substances just named present great diversities of appear- 
ance and physical characters, they are identical in a cer- 
tain chemical sense, as by burning they all yield the same 
product, viz. : carbonic acid gas. 

That carbon constitutes a large part of plants is evident 
from the fact that it remains in a tolerably pure state after 
the incomplete burning of wood, as is illustrated in the 
preparation of charcoal. 



* Rarely, or to a slight extent, lithium, rubidium, iodine, bromine, fluorine, 
barium, coppei', zinc, and titanium. 



32 HOW CROPS GKOW. 

Exp. 2,— If a splinter of diy pine -wood be set on fire and the 
burning end be gradually passed into the mouth of a narrow tube, (see 
figure 1,) -whereby the supply of air is cut ofi", or if it be 
thrust into sand, the burning is incomplete, and a stick of 
charcoal remains. 

Carhonization and charring are terms used to 
express the blackening of organic bodies by beat, 
and are due to the separation of carbon in the 
free or uncombined state. 

The presence of carbon in animal matters also is 
shown by subjecting them to incomplete com- 
bustion. 

Exp. 3.— Hold a knife-blade in the flame of a tallow candle ; 
the full access of air is thus prevented,— a portion of carbon -J^ ^ 
escapes combustion, and is deposited on the blade in the form °' 
of lamp-black. 

on of turpentine and petroleum (kerosene,) contain so 
much carbon that a portion escapes in the free state as 
smoke, when they are set on fire. 

When bones are strongly heated in closely covered iron 
pots, until they cease yielding any vapors, there remains 
in the vessels a mixture of impure carbon with the earthy 
matter (phosphate of lime) of the bones, which is largely 
used in the arts, chiefly for refining sugar, but also in the 
manufacture of fertilizers under the name of animal char- 
coal, or bone-black. 

Lignite, bituminous coal, coJce — ^the porous, hard, and 
lustrous mass left when bituminous coal is heated with a 
limited access of air, and the metallic appearing ^as-carJo/i 
that is found lining the iron cylinders in which illuminat- 
ing coal-gas is prepared, consist chiefly of carbon. They 
usually contain more or less incombustible niatters, as well 
as oxygen, hydrogen, and nitrogen. 

The difierent forms of carbon possess a greater or less de- 
gree of porosity and hardness, according to their origin 
and the temperature at which they are prepared. 

Carbon, in most of its forms, is extremely indestructible, 



THE VOLATILE PART OF PLAKTS. 33 

unless exposed to an elevated temperature. Hence stakes 
and fence posts, if charred before setting in the ground, 
last longer than when this treatment is neglected. 

The porous varieties of carbon, especially wood charcoal 
and bone-black, have a remarkable power of absorbing 
gases and coloring matters, which is taken advantage of 
in the refining of sugar. They also destroy noisome 
odors, and are therefore used for purposes of disinfection. 

Carbon is the characteristic ingredient of all organic 
compounds. There is no single substance that is the ex- 
clusive result of vital organization, no ingredient of the 
animal or vegetable produced by their growth, that does 
not contain this element. 

Oxygen. — Carbon is a solid, and is recognized by our 
senses of sight and feeling. Oxygen, on the other hand, 
is invisible, odorless, tasteless, and not distinguishable 
in any way from ordinary air by the unassisted senses. It 
is an air or gas. 

It exists in the free (uncombined) state in the atmos- 
phere we breathe, but there is no means of obtaining it 
pure except from some of its compounds. Many metals 
unite readily with oxygen, forming compounds (oxides) 
which by heat separate again into their ingredients, and 
thus furnish the means of procuring pure oxygen. Iron 
and copper when strongly heated and exposed to the air 
acquire oxygen, but from the oxides of these metals 
(forge cinder, copper scale,) it is not possible to separate 
pure oxygen. If, however, the metal mercury (quicksil- 
ver) be kept for a long time at a boiling heat, it is slowly 
converted into a red powder (red precipitate or oxide of 
mercury), which on being more strongly heated is decom- 
posed, yielding metallic mercury and gaseous oxygen in 
a pure state. 

The substance usually employed as the most convenient 
source of oxygen gas is a white salt, the chlorate of pot- 
2* 



34 



HOW CEOPS GROW. 



ash. Exposed to heat, this body melts, and presently 
evolves oxygen in great abundance. 

Exp. 4.— The following figure illustrates the apparatus employed for 
preparing and collecting this gas. 

A tube of difficultly fusible glass, 8 inches long and J^ inch wide, con- 
tains the oxide of mercury or chlorate of potash.* To its mouth is con- 
nected, air-tight, by a cork, a narrow tube, the free extremity of which 
passes under the shelf of a tub nearly filled with water. The shelf has 
beneath, a saucer-shaped cavity opening above by a narrow orifice, over 
which a bottle filled with Avatcr is inverted. Heat being applied to the 




Fig. 2. 

wide tube, the common air it contains is first expelled, and presently, 
oxygen bubbles rapidly into the bottle and displaces the water. When 
the bottle is full, it may be corked and set aside, and its place supplied 
by another. Fill four pint bottles with the gas, and set them aside with 
their mouths in tumblers of water. From one ounce of chlorate of pot- 
ash about a gallon of oxygen gas may be thus obtained, which is not 
quite pure at first, but becomes nearly so on standing over water for 
some houi'S. When the escape of gas becomes slow and cannot be 
quickened by increased heat, remove the delivery-tube from the water, 
to prevent the latter receding and breaking the apparatus. 



* The chlorate of potash is best mixed Avith about one-quarter its weight of 
powdered black oxide of manganese, as this facilitates the preparation, and ren- 
ders the heat of a common spirit lamp snfficient. 



THE VOLATILE PART OF PLANTS. 35 

As this gas makes no peculiar impressions on the senses, 
we employ its behavior towards other bodies for its recog- 
nition. 

Exp. 5.— Place a burnin<? splinter of wood in a vessel of oxygen (lift- 
ed for that purpose, mouth upward, from the water). The flame is at 
once greatly increased in brilliancy. Now remove the splinter from the 
bottle, blow out the flame, and thrust the still glowing point into the 
oxj'gen. It is instantly relighted. The experiment may be repeated 
many times. This is the usual test for oxygen gas. 

Combusiion. — When the chemical union of two bodies 
takes place with such energy as to produce visible phe- 
nomena of fire or flame, the process is called combustion. 
Bodies that burn are combustibles, and the gas in which 
a substance burns is called a supporter of combustion. 

Oxygen is the grand supporter of combustion, and all 
the cases of burning met with in ordinary experience are 
instances of chemical union between the oxygen of the at- 
mosphere and some other body or bodies. 

The rapidity or intensity of combustion depends upon 
the quantity of oxygen and of the combustible that unite 
within a given time. Forcing a stream of air into a fire 
increases the supply of oxygen and excites a more vigor- 
ous combustion, whether it be done by a bellows or re- 
sult from ordinary draught. 

Oxygen exists in our atmosphere to the extent of about 
one-fifth of the bulk of the latter. When a burning body 
is brought into unmixed oxygen, its combustion is, of 
course, more rapid than in ordinary air, four-fifths of 
which is a gas, presently to be noticed, that is nearly in- 
different in its chemical afiinities toward most bodies. 

In the air a piece of burning charcoal soon goes out ; 
but if plunged into oxygen, it burns with great rapidity 
and brilliancy. 

Exp. 6.— Attach a slender bit of charcoal to one end of a sharpened 
wire that is passed through a wide cork or card ; heat the charcoal to 
redness in the flame of a lamp, and then insert it into a bottle of oxygen) 



36 



HOW CROPS GROAY. 




Fig. 3. 



fig. 3. When the combustion has declined, a suitable test applied to the 
air of the bottle will demonstrate that another invisible gas has taken 
the place of the oxygen. Such a test is lime-water.'^ 
On pouring some of this into the bottle and agitating 
vigorously, the previously clear liquid becomes milky, 
and on standing, a white deposit, or precipitate, as the 
chemist terms it, gathers at the bottom of the vessel. 
Carbon, by thus uniting to oxygen, yields carbonic acid 
gas, vrhicli in its turn combines with lime, producing 
carbonate of lime. These substances will be further 
noticed in a subsequent chapter. 

Metallic iron is incombustible in the at- 
mosphere under ordinary circumstances, but 
if heated to redness and brought into pure 
oxygen gas, it burns as readily as wood burns in the air. 
Exp. 7. — Provide a thin knitting needle, heat one end red hot, and 
sharpen it by means of a file. Thrust the point thus 
made into a splinter of wood, (a bit of the stick of a 
match, }£ inch long;) pass the other end of the needle 
through a wide, flat cork for a support, set the wood on 
fire, and immerse the needle in a bottle of oxj'gen, fig. 
4. After the wood consumes, the iron itself takes fire 
and burns with vivid scintillations. It is converted 
into oxide of iron, a part of which will be found as a 
yellowish-red coating on the sides of the bottle ; the 
remainder will fuse to black, brittle globules, which 
falling, often melt quite into the glass. Pio-. 4. 

The only essential difference between these and ordinary 
cases of combustion is the intensity with which thj3 pro- 
cess goes on, due to the more rapid access of oxygen to the 
combustible. 

Many bodies unite slowly with oxygen — oxidize, as it 
is termed, — without these phenomena of light and intense 
heat which accompany combustion. Thus iron rusts., lead 
tarnishes, wood decai/s. All these processes are cases of 
oxidation, and cannot go on in the absence of oxygen. 

Since the action of oxygen on wood and other organic 




* To prepare lime-water, put a piece of unslaked lime, as large as a chestnut, 
into a pint of water, and after it has fallen to powder, agitate the whole for a 
minute iu a well stoppered bottle. On standing, the excess of lime will settle, 
and the perfectly clear liquid above it is ready for use. 



THE VOLATILE PART OP PLANTS. 37 

matters at common temperatures is strictly analogous in a 
chemical sense to actual burning, Liebig has proposed the 
term eremacausis^ (slow burning), to designate the chemi- 
cal process which takes place in decay and putrefaction, 
and which is concerned in many transformations, as in the 
making of vinegar and the formation of saltpeter. 

Oxygen is necessary to organic life. The act of breath- 
ing introduces it into the lungs and blood of animals, 
where it aids the important office of respiration. Ani- 
mals, and plants as well, speedily perish if deprived of 
free oxygen, which has therefore been called vital air. 

Oxygen has a universal tendency to combine with other 
substances, and form Avith them new compounds. With 
carbon, as we have seen, it forms carbonic acid. With 
iron, it unites in various proportions, giving origin to sev- 
eral distinct oxides^ of which iron-rust is one, and anvil- 
scales another. In decay, putrefaction, fermentation, and 
respiration, numberless new products are formed, the re- 
sults of its chemical affinities. 

Oxygen is estimated to be the most abundant body in 
nature. In the free state, but mixed with other gases, it 
constitutes one-fifth of the bulk of the atmosphere. In 
chemical union with other bodies, it forms eight-ninths of 
the weight of all the water of the globe, and one-third of 
its solid crust — its soils and rocks, — as well as of all the 
plants and animals which exist upon it. In fact there are 
but few compound substances occurring in ordinary expe- 
rience into which oxygen does not enter as a necessary 
ingredient. 

Nitrogen. — This body is the other chief constituent of 
the atmosphere, in which its office might appear to be 
mainly that of diluting and tempering the affinities of 
oxygen. Indirectly, however, it serves other most impor- 
tant uses, as will presently be seen. 

For the preparation of nitrogen we have only to remove 
the oxygen from a portion of atmospheric air. This may 



38 HOW CROPS GROW. 

be accomplislied more or less perfectly by a variety of 
methods. We have just learned that the process of burn- 
ing is a chemical union of oxygen with the combustible. 
If, now, we can find a body which is very combustible and 
one which at the same time yields by union with oxygen 
a product that may be readily removed from the air in 
which it is formed, the preparation of nitrogen from ordi- 
nary air becomes easy. Such a body is phosphorus^ a 
substance to be noticed in some detail presently. 

Exp. 8. — The bottom of a dinner-plate is coyercd half an inch deep 
with water, a bit of chalk hollowed out into a little cup is floated on the 
water by means of a large flat cork or a piece of wood ; into this cup a 
morsel of dry phosphorus as large as a pepper-corn is 
placed, which is then set on fire and covered by a 
capacious glass bottle or bell jar. The phosphorus 
bui-ns at first with a vivid light, which is presently ob- 
scured by a cloud of snow-like phosphoric acid. The 
combustion goes on, however, until nearly all the oxygen 
is removed from the included air. The air is at first ex- 
panded by the heat of the flame, and a portion of it es- 
capes from the vessel; afterward it diminishes in volume _,. w 
as its oxygen is removed, so that it is needful to pour °* 
water on the plate to prevent the external air from passing into the 
vessel. After some time the Avhite fume will entirely fall, and be absorbed 
by the Avater, leaving the inclosed nitrogen quite clear. 

Exp. 9. — Another instructive method of preparing nitrogen is the fol- 
lowing : A handful of copperas (sulphate of j^rotoxide of iron) is dis- 
solved in half a pint of water, the solution is put into a quart bottle, a 
gill of liquid ammonia or fresh potash lye is added, the bottle stopper- 
ed, and the mixture vigorously agitated for some minutes ; the stopper 
is then lifted, to allow fresh air to enter, and the whole is again agitated 
as before; this is repeated occasionally for half an hour or more, until 
no further absorption takes place, when nearly pure nitrogen remains in 
the bottle. 

Free nitrogen, under ordinary circumstances, has scarce- 
ly any active properties, but is best characterized by its 
chemical indifference to most other bodies. That it is in- 
capable of supporting combustion is proved by the first 
method we have instanced for its preparation. 

Exp. 10. — A burning splinter is immersed in the bottle containing the 
nitrogen prepared by the second method, Exp. 9; the flame immediately 
goes out. 




THE VOLATILE PART OF PLANTS. 39 

Nitrogen cannot maintain respiration, so that animals 
perish if confined in it. For this reason it was formerly 
called Azote (against life). Decay does not proceed in an 
atmosphere of this gas, and in general it is difficult to ef- 
fect its direct union with other bodies. At a high tem- 
perature, especially in presence of baryta, it unites with 
carbon, forming cyanogen — a compound existing in Prus- 
sian-blue. 

The atmosphere is the great'store and source of nitrogen 
in nature. In the mineral kingdom, especially in soils, 
it occurs in small quantity as an ingredient of saltpeter 
and ammonia. It is a small but constant constituent of 
all plants, and in the animal it is a never-failing component 
of the working tissues, the muscles, tendons and nerves, 
and is hence an indispensable ingredient of food. 

Hydrogen I — Water, which is so abundant in nature, 
and so essential to organic existence, is a compound of 
two elements, viz. : oxygen, that has already been con- 
sidered, and hydrogen, which Ave now come to notice. 

Hydrogen, like oxygen, is a gas, destitute, when pure, 
of either odor, taste, or color. It does not occur naturally 
in the free state, except in small quantity in the emana- 
tions from boiling springs and volcanoes. Its preparation 
almost always consists in abstracting oxygen from water 
by means of agents which have no special affinity for hy- 
drogen, and therefore leave it uncombined. 

Sodium, a metal familiar to the chemist, has such an at- 
traction for oxygen that it decomposes water with great 
rapidity. 

Exp. 11. — Hydrogen is therefore readily procured by inverting a bot- 
tle full of water in a bowl, and inserting into it a bit of sodium as large 
as a pea. The sodium must first be wiped free from the naphtha in 
which it is kept, and then be wrapped tightly in several folds of paper. 
On bringing it, thus prepared, under the mouth of the bottle, it floats 
upward, and when the water penetrates the paper, an abundant escape 
of gas occurs. 

Metallic iron and zinc decompose water, uniting with 



40 



HOW CROPS GROW. 



oxygen and setting hydrogen free. This action is almost 
imperceptible, however, with pure water under ordinary 
circumstances, because the metals are soon coated with a 
film of oxide which prevents further contact. If to the 
water a strong acid be added, or, in case zinc is used, an 
alkali, the production of hydrogen goes on very rapidly, 
because the oxide is dissolved as fast as it forms, and a 
perfectly pure metallic surface is constantly presented to 
the water. 

Exp. 12, — Into a bottle fitted with cork, funnel, and delivery tubes, 
fig. 6, an ounce of iron tacks 
or zinc clippings is introduced, 
a gill of water is poured upon 
tbem, and lastly an ounce of 
oil of vitriol is added. A brisk 
efiervescence shortly com- 
mences, owing to the escape 
of nearly pure hydrogen gas, 
which may be collected in a 
bottle filled Avith water as 
directed for oxygen. The 
first portions that pass over 
are mixed with air, and should 
be rejected, as the mixture is 
dangerously explosive. 

One of the most strik- 
ing proj)erties of free 
hydrogen is its levity. It is the lightest body in nature, 
being fourteen and a half times lighter than common air. 
It is hence used in filling balloons. 
Another property is its combustibili- 
ty: it inflames on contact with a 
lighted taper, and burns with a flame 
which is intensely hot, though scarce- 
ly luminous if the gas be pure. Final- 
ly, it is itself incapable of support- 
ing the combustion of a taper. 

Exp. 13.— All these characters may be shown by the following single 
experiment. A bottle full of hydrogen is lifted from the water over 
which it has been collected, and a taper attached to a bent wire, fig. 7, is 




Fig. 6. 




THE TOLA TILE PAKT OP PLANTS. 41 

brought to its mouth. At first a slight explosion is heard from the sudden 
burnino" of a mixture of the gas with air that forms at the mouth of the 
vessel ; then the gas is seen burning on its lower surface with a pale flame. 
If now the taper be passed into the bottle it will be extinguished ; on low- 
ering it again, it will be relighted by the burning gas ; finally, if the bot- 
tle be suddenly turned mouth upwards, the light hydrogen rises in a 
sheet of flame. 

In the above experiment, the hydrogen burns only where 
it is in contact with atmospheric oxygen ; the product of 
the combustion is an oxide of hydrogen, the universally dif- 
fused compound, water. The conditions of the experiment 
do not permit the collection or identification of this wa- 
ter; its production can, however, readily be demon- 
strated. 

Exp. 14.— The arrangement shown in fig. 8 may be employed to ex- 
hibit the formation of water by the burning of hydrogen. Hydrogen 
gas is generated from zinc and dilute acid in the two-neckdd bottle. 
Thus produced, it is mingled with vapor of water, to remove which it 




Fig. 8. 

is made to stream slowly through a wide tube filled with fragments of 
dried chloride of calcium, which desiccates it perfectly. After air has 
been entirely displaced from the apparatus, the gas is ignited at the up- 
curved end of the narrow tube, aud a clean bell-glass is supported over 
the flame. Water collects at once, as dew, on the interior of the bell, 
and shortly flows down in drops into a vessel placed beneath. 

In the mineral world we scarcely find hydrogen occur- 
ring in much quantity, save as water. It is a constant in- 
gredient of plants and animals, and of nearly all the 
numberless substances which are products of organic life. 



42 HOW CROPS GROW. 

Hydrogen forms with carbon a large number of com- 
pounds, the most common of which are the volatile oils, 
like oil of turpentine, oil of lemon, etc. The chief illumi- 
nating ingredient of coal-gas (ethylene or olefiant gas,) 
the coal or rock oils, (kerosene,) together with benzine 
and paraffine, are so-called hydro-carbons. 

Sulphur is a well-known solid substance, occurring in 
commerce either in sticks (brimstone, roll sulphur,) or as 
a fine powder (flowers of sulphur), having a pale yellow 
color, and a peculiar odor and taste. 

Uncombined sulphur is comparatively rare, the com- 
mercial supplies being almost exclusively of volcanic ori- 
gin ; but in one or other form of combination, this element 
is universally diffused. 

Sulphur is combustible. It burns in the air with a pale 
blue flame, in oxygen gas with a beautiful purple-blue flame, 
yielding in both cases a suffocating and fuming gas of 
peculiar nauseous taste, which is called sulphurous acid. 

Exp. 15.— Heat a bit of sulphur as large as a grain of wheat on a slip 
of iron or glass, in the flame of a spirit lamp, for observing its fusion, 
combustion, and the development of sulphurous acid. Further, scoop 
out a little hollow in a piece of chalk, twist a wire around the latter to 
serve for a handle, as in fig. 3 ; heat the chalk with a fragment of sulphur 
upon it until the latter ignites, and bring it into a bottle of oxygen gas. 
The purple flame is shortly obscured by the opaque white fume of the 
sulphurous acid. 

Sulphur forms with oxygen another compound, which, 
in combination with water, constitutes common sulphuric 
acid, or oil of vitriol. This is developed to a slight ex- 
tent by the action of air on flowers of sulphur, but is pre- 
pared on a large scale for commerce by a complicated 
process. 

Sulphur unites with most of the metals, yielding com- 
pounds known as sulphides or sulphurets. These exist in 
nature in large quantities, especially the sulphides of iron, 
copper, and lead, and many of them are valuable ores. 



THE VOLATILE PART OF PLANTS. 43 

Sulphides may be formed artificially by heating most of 
the metals with sulphur. 

Exp. 16.— Heat the bowl of a tobacco pipe to a low red heat in a stove 
or furnace ; have in readiness a thin iron wire or watch-spring made into 
a spiral coil ; throw into the pipe-bowl some lumps of sulphur, and when 
these melt and boil with formation of a red vapor or gas, introduce the 
iron coil, previously heated to redness, into the sulphur vapor. The 
sulphur and iron unite ; the iron, in fact, burns in the sulphur gas, giv- 
ing rise to a blade sulphide of iron, in the same manner as in Exp. 7 it 
burned in oxygen gas and produced an oxide of iron. The sulphide of 
iron melts to brittle, round globules, and remains in the pipe-bowl. 

With hydrogen^ the element we are now considering 
unites to form a gas that possesses in a high degree the 
odor of rotten eggs, which is, in fact, the chief cause of 
the noisomeness of this kind of putridity. This substance, 
commonly called sulphuretted hydrogen^ also sulphydric 
acid^ is dissolved in, and evolved abundantly from, the 
water of sulj^hur springs. It may be produced artificially 
by acting on some metallic sulphides with dilute sulphuric 
acid. 

Exp. 17. — Place a lump of the sulphide of iron prepared in Exp. 16 in 
a cup or wine-glass, add a little water, and lastly a few drops of oil of 
vitriol. Bubbles of sulphuretted hydrogen gas will shortly escape. 

In soils, sulphur occurs almost invariably in the form 
of sulphates, compounds of sulphuric acid with metals, 
a class of bodies to be hereafter noticed. 

In plants, sulphur is always present, though usually in 
small quantity. The turnip, the onion, mustard, horse- 
radish, and assafcetida, owe their peculiar flavors to volatile 
oils in which sulphur is an ingredient. 

Albumin, gluten and casein, — ^vegetable principles never 
absent from plant or animal, — possess also a small content 
of sulphur. In hair and horn it occurs to the amount of 
3 to 5 per cent. 

When organic matters are burned with full access of 
air, their sulphur is oxidized and remains in the ash as 
sulphuric acid, or escapes into the air as sulphurous acid. 

Phosphorus is an element which has such intense af^ 



44 HOW CBOPS GEOW. 

finities for oxygen that it never occurs naturally in the 
free state, and when prepared by art, is usually obliged to 
be kept immersed in water to prevent its oxidizing, or 
even taking fire. It is known to the chemist in the solid 
state in two distinct forms. In the more commonly occur- 
ring form, it is colorless or yellow, translucent, wax-like in 
appearance ; is intensely poisonous, inflames by moderate 
friction, and is luminous in the dark, hence its name, de- 
rived from two Greek words signifying light-hearer. The 
other form is brick red, opaque, far less inflammable, and 
destitute of poisonous properties. Phosphorus is exten- 
sively employed for the manufacture of friction matches. 
For this purpose yellow phosphorus is chiefly used. 

When exposed sufiiciently long to the air, or immedi- 
ately, on burning, this element unites with oxygen, form- 
ing a body of the utmost agricultural importance, viz. ; 
phosphoric acid. 

Exp. 18. — Burn a bit of pliosphorus under a bottle as in Exp. 8, omit- 
ting the water on the plate. The snow-like cloud of phosphoric acid 
gathers partly on the sides of the bottle, but mostly on the plate. It 
attracts moisture when exposed to the air, and hisses when put into wa- 
ter. Dissolve a portion of it in water, and observe that the solution is 
acid to the taste. 

In nature phosphorus is usually found in the form of 
phosphates^ which are compounds of metals with phos- 
phoric acid. 

In plants and animals, it exists for the most part as 
phosphates of lime, magnesia, potash, and soda. 

The bones of animals contain a considerable proportion 
(10 per cent) of phosphorus mainly in the form of phos- 
phate of lime. It is from them that the phosphorus em- 
ployed for matches is largely procured. 

Exp. 19. — Burn a piece of bone in a fire until it becomes white, or 
nearly so. The bone loses about half its weight. What remains is 
bone-earth or bone-ash, and of this 90 per cent is phosphate of lime. 

Phosphates are readily formed by bringing together so- 
lutions of various metals with solution of phosphoric acid. 

Exp. 20.— Pour into each of two wine or test glasses a small quantity 



THE VOLATILE PAKT OP PLANTS. 45 

of the solution of phosphoric acid obtained in Exp. 18. To one, add 
some lime-water (see note p. 36) until a white cloud ov precipitate is per- 
ceived. This is a phosphate of lime. Into the other portion, drop solu- 
tion of alum. A translucent cloud of pJiosphaie of alumina is immediately 
produced. 

In soils and rocks, phosphorus exists in the state of 
such phosphates of lime, alumina, and, iron. 

In the organic world the chemist has as yet detected 
phosphorus in other states of combination in but a few 
instances. In the brain and nerves, and in the yolk of 
eggs, an oil containing phosphorus has been known for 
some years, and recently similar phosphorized oils have 
been found in the pea, in maize, and other grains. 

"We have thus briefly noticed the more important char- 
acters of those six bodies which constitute ,that part of 
plants, and of animals also, which is volatile or destruct- 
ible at high temperatures, viz. : carbon, hydrogen, oxygen, 
nitrogen, sulphur, and phosphorus. 

Out of these substances chiefly, which are often termed 
the organic elements of vegetation, are compounded all 
the numberless products of life to be met with, either in 
the vegetable or animal world. 

tTLTTMATE COMPOSITION^" OF VEGETABLE MATTEE. 

To convey an idea of the relative proportions in which 
these six elements exist in plants, a statement of the 
ultimate or elementary percentage composition of several 
kinds of vegetable matter is here subjoined. 

Grain of Slrato of Tubers of Grain of Bay of Bed 
WJieat. Wheat. Potato. Peas. Clover. 

Carbon 46.1 48.4 44.0 46.5 47.4 

Hydrogen 5.8 5.3 5.8 6.3 5.0 

Oxygen 43.4 38.9 44.7 40.0 37.8 

Nitrogen 2.-3 0.4 1.5 4.2 2.1 

Ash, including sulphur \ ^ a /yn ac\ qi 't'? 

and phosphorus f "'•^ '•" *•" ^'^ ''^ 

100.0 100.0 100.0 100.0 100.0 

Sulphur. 0.12 0.14r 0.08 0.21 0.18 

Phosphorus 0.30 0.80 0.34 0.34 0.20 



46 HOW CROPS GEOW. 

Our attention may now be directed to the study of such 
compounds of these elements as constitute the basis of 
plants in general ; since a knowledge of them will prepare 
us to consider the remaining elements with a greater de- 
gree of interest. 

Previous to this, however, we must, first of all, gain a 
clear idea of that force or energy, in virtue of whose action, 
chiefly, these elements are held in, or separated from their 
combinations. 

§3. 

CHEMICAL AFFINITY. 

Chemical attraction or affinity is the force which unites 
or combines two or more substances of unlike character ^to 
a new body different from its ingredients. 

Chemical combination differs essentially from mere mix- 
ture. Thus we may mix together in a vessel the two gases 
oxygen and hydrogen, and they will remain uncombined 
for an indefinite time, occupying their original volume; 
but if a flame be brought into the mixture they instantly 
unite with a loud explosion, and in place of the light and 
bulky gases, we find a few drops of water, which is a liquid 
at ordinary temperatures, and in winter weather becomes 
solid, which does not sustain combustion like oxygen, nor 
itself burn as does hydrogen ; but is a substance having its 
own peculiar properties, differing from those of all other 
bodies with which we are acquainted. 

In the atmosphere we have oxygen and nitrogen in a 
state of mere mixture, each of these gases exhibiting its 
own characteristic properties. When brought into chemi- 
cal combination, they are capable of yielding a series of 
no less than five distinct compounds, one of which is the 
so-called laughing gas, while the others form suffocating 
and corrosive vapors that are totally ii-respirable. 



THE VOLATILE PART OF PLANTS. 47 

Chemical decomposition. — ^Water, thus composed or 
put together "by the exercise of affinity, is easily decom- 
posed or taken to pieces, so to speak, by forces that op- 
pose affinity— e. g., heat and electricity — or by the greater 
affinity of some other body — e. g., sodium — as already 
illustrated in the preparation of hydrogen, Exp. 11. 

Definite proportions* — ^A further distinction between 
chemical union and mere mixture is, that, while two or 
more bodies may, in general, be mixed in all proportions, 
bodies combine chemically in comparatively few propor- 
tions, which are fixed and invariable. Oxygen and hydro- 
gen, e. g., are found united in nature, principally in the 
form of water ; and water, if pure, is always composed of 
exactly one-ninth hydrogen and eight-ninths oxygen by 
weight, or, since oxygen is sixteen times heavier than 
hydrogen, bulk for bulk, of one volume or measure of 
oxygen to two volumes of hydrogen. 

Atomic Weiglit of Elements.— On the hypothesis 
that chemical union takes place between atoms or indi- 
visible particles of the elements, the numbers expressing 
the proportions by weight* in which they combine, are 
appropriately termed atomic weights. These numbers are 
only relative, and since hydrogen is the element which 
unites in the smallest proportion by weight, it is assumed 
as the standard. From the results of a great number of 
the most exact experiments, chemists have generally agreed 
upon the atomic weights given in the subjoined table for 
the elements already mentioned or described. 

Sym1)0ls. — ^For convenience in representing chemical 
changes, the first letter, (or letters,) of the Latin name of 
the element!^ employed instead of the name itself, and is 
termed its symbol. 



* ITnless plherwise st^^ted, parts or proportions by wdght are always to be 
unde|rgtpp#. 



48 HOW CROPS GROW. 

TABLE OF ATOMIC WEIGHTS AND SYMBOLS OF ELEMENTS.* 



JElement. 


At. wt. 


Symbol. 


Hydrogen 


1 


H 


Carbon 


12 


C 


Oxygen 


}^ 





Nitrogen 


U 


N" 


Sulphur 


32 


s 


Phosphorus 


31 


p 


Chlorine 


35.5 


CL 


Mercury 


200 


Hg (Hydrargyrum) 


Potassium 


39 


K (Kalium) 


Sodium 


23 


Na (Natrium) 


Calcium 


40 


Ca 


Iron 


56 


Fe (Ferrum) 



Multiple Proportions. — When two or more bodies unite 
in several proportions, their quantities, when not expressed 
by the atomic weights, are twice, thrice, four, or more times, 
these weights ; they are multiples of the atomic weights by 
some simple number. Thus, carbon and oxygen form two 
commonly occurring compounds, viz., carbonic, oxide^ con- 
sisting of one atom of each ingredient, and carbonic acid^ 
which contains to one atom, or 12 parts by weight, of car- 
bon, two atoms, or 32 parts by weight, of oxygen. 

Molecular Weights of Compounds. — ^While elements 
unite by indivisible atoms, to form compounds, the 
compounds themselves combine with each other, or 
exist as molecules, \ or aggregations of atoms. It has 
indeed been customary to speak of atoms of a com- 
pound body, but this is an absurdity, for the smallest par- 
ticles of comj)ounds admit of separation into their elements. 
The term molecule implies capacity for division just as 
atom excludes that idea. 



* Latterly, chemists are mostly inclined to receive as the true atomic weights 
ctofuMe the numbers that have heen commonly employed, hydrogen, chlorine, 
and a few others excepted. 

+ Latin diminutive, signifying a UtUe mass. 



THE VOLATILE PAET OP PLANTS. 49 

The molecular weight of a compound is the sum of the 
weights of the atoms that compose it. For example, wa- 
ter being composed of 1 atom, or 16 parts by weight, of 
oxygen, and 2 atoms, or 2 parts by weight, of hydrogen, 
has the molecular weight of 18. 

The following scheme illustrates the molecular compo- 
sition of a somewhat complex compound, one of the car- 
bonates of ammonia. 

Ammonia gas results from the anion of an atom of 
nitrogen with three atoms of hydrogen. One molecule 
of ammonia gas unites with a molecule of carbonic acid 
gas and a molecule of water, to produce a molecule of 
carbonate of ammonia. 



f Ammonia _ j Hydrogen, 3 ats. = 3 ) ^„ ^-,.i.^ 
Carbonate ^ ^«^- ~ < Nitrogen, 1 " = 14 f "" P^^^^ 

^^^r ?^^i Carbonic acid, ( Carbon, 1 " = 12 ( .. ^_.„ 



Ammonia 



of 1 mol -i Carbonic acid, j Carbon, 1 " = 12 l^ ^ 

ot inaol.-^ 1 mol. = 1 Oxygen, 2 " = 32 f =** P^'^^^ 

Water, _J Hydrogen, 2 " = 2 I _-. q T,arts 

1 mol. -] Oxygen, 1 " =i6r-i«Parts 



=79 parts. 



Notation of Compounds. — For the purpose of express- 
ing easily and concisely the composition of compounds, 
and the chemical changes they undergo, chemists have 
agreed to make the symbol of an element signify one atom 
of that element. 

Thus H implies not only the light, combustible gas hy- 
drogen, but one part of it by weight as compared with other 
elements, and S suggests, in addition to the idea of the 
body sulphur, the idea of 32 parts of it by weight. Through 
this association of the atomic weight with the symbol, the 
composition of compounds is expressed in the simplest 
manner by writing the symbols of its elements one after 
the other, thus: carbonic oxide is represented by C O, 
oxide of mercury by Hg O, and sulphide of iron by Fe S. 
C O conveys to the chemist not only. the fact of the 
existence of carbonic oxide, but also instructs him that its 
molecule contains an atom each of carbon and of oxygen, 
and from his knowledge of the atomic weights he gathers 
the proportions by weight of the carbon and oxygen in it. 
3 



50 HOW CEOPS GEOW. 

When a compound contains more than one atom of an 
element, this is shown by appending a small figure to the 
symbol of the latter. For example : water consists of 
two atoms of hydrogen united to one of oxygen, the 
symbol of water is then H^ O. In like manner the symbol 
of carbonic acid is C O^. 

When it is wished to indicate that more than one mole- 
cule of a compound exists in combination or is concerned 
in a chemical change, this is done by prefixing a large 
figure to the symbol of the compound. For instance, 
two molecules of water are expressed by 2 H^ O. 

The symbol of a compound is usually termed 2, formula. 
Subjoined is a table of the formulas of some of the com- 
pounds that have been already described or employed. 

POEMULAS OP COMPOUNDS. 

^olecular weight, 
18 
34 
88 
216 
44 
111 
64 
80 
142 
Empirical and Rational Formulas.— It is obvious that 
many different formulas can be made for a body of com- 
plex character. Thus, the carbonate of ammonia, whose 
composition has ah-eacly been stated, (p. 49,) and which 
contains 

1 atom of Nitrogen, 
1 " " Carbon, 
3 atoms " Oxygen, and 
5 " " Hydrogen, 
may be most compactly expressed by the symbol 
N C 0„ H . 



Name. 


Formula 


Water 


H,0 


Sulphydric acid 


H,S 


Sulphide of iron 


FeS 


Oxide of Mercury 


HgO 


Carbonic acid (anhydrous) 


00, 


Chloride of calcium 


CaCl, 


Sulphurous acid (anhydrous) 


SO, 


Sulphuric acid 


SO, 


Phosphoric acid 


P«0. 



THE VOLATILE PAKT OP PLANTS. 51 

Such a formula merely informs us what elements and 
how many atoms of each element enter into the composi- 
tion of the substance. It is an empirical formula, being 
the simplest expression of the facts obtained by analysis 
of the substance. 

Rational formulas, on the other hand, are intended to 
convey some notion as to the constitution, formation, or 
modes of decomposition of the body. For example, the 
fact that carbonate of ammonia results from the union 
of one molecule each of carbonic acid, water, and ammonia, 
is expressed by the formula 

K H3, H, O, C O,. 

A substance may have as many rational formulas as 
there are rational modes of viewing its constitution. 

Equations of Formulas serve to explain the results of 
chemical reactions and changes. Thus the breaking up 
by heat of chlorate of potash into chloride of potassium 
and oxygen, is expressed by the following statement. 
Chlorate of potash. Chloride of potassium. Oxygen. 
KCIO, == KCl + O3 

The sign of equality, =, shows that what is written be- 
fore it supplies, and is resolved into what follows it. The 
sign + indicates and distinguishes separate compounds. 

The employment of this kind of short-hand for exhibit- 
ing chemical changes will find frequent illustration as we 
proceed with our subject. 

Modes of Stating Composition of Chemical Compounds. 

— These are two, viz., atomic or molecular statements and 
centesimal statements, or proportions in one hundred parts, 
{per cent, p. c. or "j „.) These modes of expressing com- 
position are very useful for comparing together difierent 
compounds of the same elements, and, while usually the 
atomic statement answers for substances which are com- 
paratively simple in their composition, the statement per 
cent is more useful for complex bodies. The composition 



52 HOW CEOPS GROW. 

of the two compounds of carbon with oxygen is given be- 
low according to both methods. 

Atomic Fer cent. Atomic. Per cent. 

Carbon, (C) 13 43.86 (C) 13 37.37 

Oxygen, (O,) 16 57.14 (O2) 33 73.73 

Carbonic oxide, (C O,) 38 100.00 Carbonic acid, (C O2,) 44 100.00 

Tlie conversion of one of tliese statements into tlie otlier is a case of 
simple rule of three, wbicli is illustrated in the following calculation of 
the centesimal composition of water from its atomic formula. 

Water, H2 0, has the molecular weight 18, i. e., it consists of two 
atoms of hydrogen, or two parts, and one atom of oxygen, or sixteen 
parts by weight. 
The arithmetical proportions subjoined serve for the calculation, viz.: 
Ha O Water H Hydrogen 

18 : 100 :: 3 : per cent sought ( =11.11 + ) 

Ha O Water O Oxygen 

18 : 100 :: 16 : per cent sought ( = 88.88 + ) 

By multiplying together the second and third terms of these propor- 
tions, and dividing by the first, we obtain the required per cent, viz., of 
hydrogen, 11.11; and of oxygen, 88.88. 

The reader must bear well in mind that chemical affinity 
manifests itself with very different degrees of intensity 
between different bodies, and is variously modified, excited, 
or annulled, by other natural agencies and forces. 

§4- 

VEGETABLE ORGANIC COMPOUNDS OR PROXIMATE 
ELEMENTS. 

We are now prepared to enter upon the study of the 
organic compounds, which constitute the vegetable struc- 
ture, and which are produced from the elements carbon, 
oxygen, hydrogen, nitrogen, sulphur, and phosphorus, -by 
the united agency of chemical and vital forces. The num- 
ber of distinct substances found in plants is practically un- 
limited. There are already well knovv^n to chemists hun- 
dreds of oils, acids, bitter principles, resins, coloring mat- 
ters, etc. Almost every plant contains some organic body 



THE VOLATILE PART OF PLANTS. 53 

peculiar to itself, and usually the same plant in its different 
parts reveals to the senses of taste and smell the presence 
of several individual substances. In tea and coffee occurs 
an intensely bitter " active principle," thein. From tobacco 
an oily liquid of eminently narcotic and poisonous proper- 
ties, nicotin^ can be extracted. In the orange are found 
no less than three oils / one in the leaves, one in the flow» 
ers, and a third in the rind of the fruit. 

N^otwithstanding the great number of bodies thus occur- 
ing in the vegetable kingdom, it is a few which form the 
bulk of all plants, and especially of those which have an agri- 
cultural importance as sources of food to man and animals. 
These substances, into which any plant may be resolved by 
simple, mostly mechanical means, are conveniently termed 
proximate elements^ and we shall notice them in some de- 
tail under six principal groups, viz : 

1. Watee. 

2. The Cellulose Group or Amyloids — Cellulose, 
(Wood,) Starch, the Sugars and Gums. 

3. The Pectose Group — the Pulp and Jellies of Fruits 
and certain Roots. 

4. The Vegetable Acids. 

5. The Fats and Oils. 

6. The Albuminoid or Protein Bodies. 

1. Water, H^ O, as already stated, is the most abundant 
ingredient of plants. It is itself a compound of oxygen and 
hydrogen, having the following centesimal composition : 

Oxygen, 88.88 

Hydrogen, 11.11 

100.00 
It exists in all parts of the plant, is the immediate cause 
of the succulence of the tender parts, and is essential to 
the life of the vegetable organs. 

In the following table arc given the percentages of water in some of 
the more common agricultural products in the /res/i state^ hut the pro- 



54 HOW CROPS GROW. 

portions are not quite constant, even in the same part of diflFerent speci- 
mens of any given plant. 

WATER {per cent) in fresh plants. 

Meadow grass 72 

Red clover 79 

Maize, as used for fodder 81 

Cabbage 90 

Potato tubers 75 

Sugar beets 83 

Carrots 85 

Turnips 91 

Pine wood 40 

In living plants, water is usually perceptible to tlie eye 
or feel, as sa}). But it is not only fresh plants that con- 
tain water. When grass is made into hay, the water is by 
no means all dried out, but a considerable proportion re- 
mains in the pores, which is not recognizable by the 
senses. So, too, seasoned wood, flour, and starch, when 
seemingly dry, contain a quantity of invisible water, which 
can be removed by heat. 

Exp. 21. — Into a wide glass tube, like that sliown in fig. 2, place a 
spoonful of saw-dust, or starch, or a little hay. Warm over a lamp, but 
A^ery slowly and cautiously, so as not to burn or blacken the substance. 
Water will be expelled from the organic matter, and will collect on the 
cold part of the tube. 

It is thus obvious that vegetable substances may con- 
tain water in two different conditions. Red clover, for 
example, Avhen growing or freshly cut, 
contains abput 79 per cent of water. 
When the clover is dried, as for making 
hay, the greater share of this water es- 
capes, so that the air-dry plant contains 
but about 17 per cent. On subjecting the 
air-dry clover to a temperature of 212° 
for some hours, the water is completely expelled, and the 
substance becomes really dry. 

To drive oflfall water from vegetable matters, the chemist usually em- 
ploys a water-hath, fig. 9, consisting of a vessel of tin or copper plate, 
with double walls, between which is a space that may be nearly filled 
with water. The substance to be dried is placed in the interior chamber. 




THE VOLATILE PART OF PLANTS. 55 

tlie door is closed, aud the water is brouglit to boil by the heat of a lamp 
or stove. The precise quantity of water belonging to, or contained in, a 
substance, is ascertained by first weighing the substance, then drying it 
until its weight is constant. The loss is water. 

In the subjoined table are given the average quantities, per cent, of 
water existing in various vegetable products when air-dry. 

WATER IN AIR-DRY PLANTS. 

Meadow grass, (hay,) 15 

Red clover hay 17 

Pine wood 20 

Straw and chaff of wheat, rye, etc 15 

Bean straw 18 

Wheat, (rye, oat,) kernel 14 

Maize kernel 13 

That portion of the water which the fresh plant loses by- 
mere exposure to the air is chiefly the water of its juices 
or sap, and is manifest to the sight and feel as a liquid, in 
crushing the fresh plant ; it is, properly speaking, the free 
water of vegetation. The water which remains in the air- 
dry plant is imperceptible to the senses while in the plant, 
— can only be discovered on expelling it by heat or other- 
wise, — and may be designated as the hygroscopic water of 
vegetation. 

The amount of water contained in either fresh or air- 
dry vegetable matter is constantly fluctuating with the 
temperature and the dryness of the atmosphere. 

2. The Cellulose Group, or the Amyloids. 
This group comprises Cellulose, Starch, Inulin, Dextrin, 
Gum, Cane sugar, Fruit sugar, and Grape sugar. 

These bodies, especially cellulose and starch, form by 
far the larger share — perhaps seven-eighths — of all the dry 
matter of vegetation, and most of them are distributed 
throughout all parts of plants. 

Cellulose, C^^ H^^ O^,. — Every agricultural plant is an 
aggregate of microscopic cells, i. e., is made up of minute 
.sacks or closed tubes, adhering to each other. 



56 



HOW CROPS GKOW. 



Fig. 10 represents an extremely thin slice from tlie stem of a cabbage, 
magnified 330 diameters. The united walls of two cells are seen in sec- 
tion at a, while at & an empty space is noticed. 




Fig. 10. 

The outer coating, or wall, of the cell is cellulose. This 
substance is accordingly the skeleton or framework of the 
plant, and the material that gives tough- 
ness and solidity to its parts. Next to 
water it is the most abundant body in 
the vegetable world. 

All plants and all parts of all plants 
contain celhdose, but it is relatively most 
abundant in their stems and leaves. In 
seeds it forms a large portion of the husk, 
shell, or other outer coating, but in the 
interior of the seed it exists in small 
quantity. 

The fibers of cotton, (Fig. 11, a,) hemp, 

and flax, (Fig. 11, Z),) and white cloth and 

unsized paper made from these materials, 

are nearly jmre cellulose. 

The fibers of cotton, hemp, and flax, are simply 

-p. long and thick-walled cells, the appeai-ance of 

'^' ' which, when highly magnified, is shown in fig. 

11, Avhere a represents the thinner, more soft, and collapsed cotton fiber, 

and b the thicker and more durable fiber of linen. 




THE VOLATILE PAET OF PLANTS. 57 

Wood, or woody fiber, consists of long and slender cells 
of various forms and dimensions, see p. 271,) which are deli- 
cate when young, (in the sap wood,) but as they become 
older fill up interiorly by the deposition of repeated layers 
of cellulose, which is intergrown with a substance, (or sub- 
stances,) called lignin.^ The hard shells of nuts and 
stone fruits contain a basis of cellulose, which is impreg- 
nated with ligneous matter. 

When quite pure, cellulose is a white, often silky or 
spongy, and translucent body, its appearance varying some- 
what according to the source whence it is obtained. In 
the air-dry state, it usually contains about 10" \^ of hygro- 
scopic water. It has, in common with animal membranes, 
the character of swelling up when immersed in water, from 
imbibing this liquid ; on drying again, it shrinks in bulk. 
It is tough and elastic. 

Cellulose difiers remarkably from the other bodies of 
this group, in the fact of its slight solubility in dilute acids 
and alkalies. It is likewise insoluble in water, alcohol, 
ether, the oils, and in most ordinary solvents. It is hence 
prepared in a state of purity by acting upon vegetable 
matters containing it with successive solvents, until all 
other matters are removed. 

The " skeletonized " leaves, fruit vessels, etc., which compose those 
beautiful objects called phantom bouquets^ are commonly made by dis- 
solving away the softer portions of fresh succulent plants by a hot solu- 



* According to F. Schulze, lignm impregnates, (not simply incrusts,) the 
cell-wall, it is soluble in hot alkaline solutions, and is readily oxidized by nitric 
acid. Schulze ascribes to it the composition 

Carbon ...55.3 

Hydrogen , 5.8 

Oxygen 38.9 

100.0 

This is, however, simply the inferred composition of what is left after the 
ceUulose, etc., have been removed. Liguin cannot be separated in the pure 
state, and has never been analyzed. What is thus designated is probably a mix- 
ture of several distinct substances. 

Lignin appears to be indigestible by herbivorous animals, {Grouven, V. Ebf- 
meister.)- 

3* 



58 HOW CROPS GROW. 

tiou of caustic sodii, and afterwards wliiteniug the skeleton of fibers that- 
remains by means of chloride of lime, (bleaching powder.) They are al- 
most pure cellulose. 

Skeletons may also be prepared by steeping vegetable matters in a mix- 
ture of chlorate of potash and dilute nitric acid for a number of days. 

Exp. S3. — To 500 cubic centimeters,^ (or one pint,) of nitric acid of 
density 1.1, add 30 grams, (or one ounce,) of pulverized chlorate of pot- 
ash, and dissolve the latter by agitation. Suspend in this mixture a 
number of leaves, etc.,+ and let them remain undisturbed, at a temper- 
ature not above 65° F., until they are perfectly whitened, which may re- 
quire from 10 to 20 days. The preparations of leaves should be floated 
out from the solutions on slips of paper, washed copiously in clear watei-, 
and dried under pressure between folds of unsized paper. 

The fibers of the whiter and softer kinds of wood are now much em- 
ployed in the fabrication of pnper. For this purpose the wood is rasped 
to a coarse powder by machinery, then freed from lignin, starch, etc., 
by a hot solution of soda, and finally bleached with chloride of lime. 

The husks of maize have been successfully employed in Austria, both 
for making paper and an inferior cordage. 

Thougli cellulose is insoluble in, or but slightly affected 
by dilute acids and alkalies, it is dissolved or altered by 
these agents, when they are concentrated or hot. The 
result of the action of strong acids and alkalies is very 
various, accordinsj to their kind and the desrree of strens^th 
in which they are employed. 

The strongest nitric acid transforms cellulose into nitrocellulose^ (pyrox- 
iline, gun cotton,) a body which burns explosively, and has been em- 
ployed as a substitute for gunpowder. 

Sulphuric acid of<a certain strength, by short contact with cellulose, con- 
verts it a tough, translucent substance which strongly resembles bladder 
or similar animal membranes. Paper, thus treated, becomes the 
parchment of commerce. 



* On subsequent pages we shall make frequent use of some of the French dec- 
imal weights and measures, for the reasons that they are much more convenient 
than the English ones, and are now almost exclusively employed in all scientific 
treatises and investigations. For small weights, the gram, abbreviated gm., 
(equal to 151^ grains, nearly), is the customary unit. The unit of measure by vol- 
ume is the cubic centimeter, abbreviated c. c, (30 c. c. equal one fluid ounce 
nearly). Gram weights and glass measures graduated into cubic centimeters are 
furnished by aU dealers in chemical apparatus. 

t Full-grovra but not old leaves of the elm, maple, and maize, heads of un- 
ripe grain, slices of the stem and joints of maize, etc., maybe employed to fur- 
nish skeletons that will prove valuable in the study of the structure of these 
organs. 



THE VOLATILE PART OF PLANTS. 59 

Exp. 23.— To prepare parchment paper, fill a large cylindrical test tube 
first to the depth of an inch or so with water, then pour in three times 
this bulk of oil of vitriol, and mis:. When the liquid is perfectly cool, im- 
merse into it a strip of unsized paper, and let it remain for about 15 sec- 
onds; then remove, and rinse it copiously in water. Lastly, soak for 
some minutes in water, to which a little ammonia is added, and wash 
again with pure water. These washings are for the purpose of removing 
the acid. The success of this experiment depends upon the proper 
strength of the acid, and the time of immersion. If need be, repeat, va- 
rying these conditions slightly, until the result is obtained. 

Prolonged contact with strong sulphuric acid converts 
cellulose into dextrin, and finally into sugar, (see p. 75.) 
Other intermediate products are, however, formed, whose 
nature is little understood ; but the properties of one of 
them is employed as a test for cellulose. 

Exp. 24. — Spread a slip of unsized paper upon a china plate, and pour 
upon it a few drops of the diluted sulphuric acid of Exp. 23. After some 
time the paper is seen to swell up and partly dissolve. Now flow it with a 
weak solution of iodine,* when these dissolved portions will assume a 
fine and intense blue color. This deportment is characteristic of cellulose, 
and may be employed for its recognition under the microscope. If the 
experiment be repeated, using a larger proportion of acid, and allowing 
the action to continue for a considerably longer time, the substance 
producing the blue color is itself destroyed or converted into sugar, and 
addition of iodine has no effect.t 

Boiling for some hours with dilute sulphuric acid also 
transforms cellulose into sugar,' and, under certain circum- 
stances, chlorhydric acid and alkalies have the same 
effect upon it. 

The denser and more impure forms of cellulose, as they 
occur in wood and straw, are slowly acted upon by chemi- 
cal agents, and are not easily digestible by most animals ; 
but the cellulose of young and succulent stems, leaves, and 
fruits, is digestible to a large extent, especially in the 
stomachs of aninials which naturally feed on herbage, anr] 
therefore cellulose ranks among the nutritive substances. 



• Dissolve a fragment of iodine as large as a wheat kernel in 20 c. c. of alco- 
hol, add 100 c. c. of water to the solution, and preserve in a well stoppered bottle. 

+ According to Grouvcn, cellulose prepared from rye sti-aw, (and impure ?) 
requires several hours' action of sulphuric acid before it mil strike a blue color 
with iodine, (2fer Salzm'lnder Bericht, p. 467.) 



60 HOW CEOPS GEOW. 

Chemical composition of ceUuloae. — This body is a com- 
pound of the three elements, carbon, oxygen, and hydro- 
gen. Analyses of it, as prepared from a multitude of 
sources, demonstrate that its composition is expressed by 
the formula, C^^ H^^ 0^„. In 100 parts it contains 

Carbon, 44.44 
Hydrogen, G.IT 
Oxygen, 49.39 

100.00 

Modes of estimating cellulose. — ^In statements of tlie composition of 
plants, the terms fiber% tooodt/ fiber, and crude cellulose, are often met with. 
These are applied to more or less impure cellulose, which is obtained as 
a residue after removing other matters, as far as possible, by alternate 
treatment with dilute acids and alkalies, hut without acting to any great 
extent on the cellulose itself The methods formerly employed, and 
those by which most of our analyses have been made, are confessedly 
imperfect. If the solvents are too concentrated, or the temperature at 
which they act is too high, cellulose itself is dissolved ; while with too 
dilute reagents a portion of other matters remains unattacked. The 
method adopted by Henneberg, ( Versuchs-Stationen, VI, 497,) with quite 
good results, is as follows: 3 grams of the finely divided substance are 
boiled for half an hour with 200 cubic centimeters of dilute sulphuric 
acid, (containing 1% per cent of oil of vitriol,) and after the substance 
has settled, the acid liquid is poured off. The residue is boiled again 
for half an hour with 200 c. c. of water, and this operation is repeated a 
second time. The residual substance is now boiled half an hour witli 
200 c. c. of dilute potash lye, (containing !}£ per cent of dry caustic 
potash,) and after removing the alkaline liquid, it is boiled twice with 
water as before. What remains is brought vipon a filter, and washed 
with water, then with alcohol, and, lastly, with ether, as long as these 
solvents take up anything. This crude cellulose contains ash and nitro- 
gen, for which corrections must be made. The nitrogen is assumed to 
belong to some albuminoid, and from its quantity the amount of the 
latter is calculated, (see p. 108.) 

Even with these corrections, the quantity of cellulose is not obtained 
with entire accuracy, as is usually indicated by its appearance and its 
composition. While, according to V. Hofmeister, the crude cellulose 
thus prepared from the pea is perfectly white, that from wheat bran is 
brown, and that from rape-cake is almost black in color. 

Grouven gives the following analyses of two samples of crude cellulose 
obtained by a method essentially the same as we have described. (2fer 
Salzmiimler Bericht, p. 456.) 



THE VOLATILE PAET OF PLANTS. 61 





Bye-straw fiber. 


Linen fiber. 


Water... 


8.65 


5.40 


Ash 


2.05 


1.14 


N 


0.15 


0.26 


C 


42.47 


38.36 


H 


6.04 


5.89 





, 40.64 


48.95 




100.00 


100.00 



On deducting water and asli, and making proper correction for tlie 
nitrogen, the above samples, together with one of wheat-straw fiber, 
analyzed by Henneberg, exhibit the following composition, compared 
with pure cellulose. 

Rye- straw fiber. Linen fiber. Wh^at-straw fiber. Fare cellulose. 

C 47.5 4L0 45.4 44.4 

H 6.8 6.4 6.3 6.3 

45.7 52.6 48.3 49.4 

100.0 100.0 100.0 100.0 

Franz Schulze, of Rostock, proposed in 1857 another method for esti- 
mating cellulose, which has recently, (1866,) been shown to be more cor- 
rect than the one already described. Kuhn, Aronstein, and H. Schulze, 
{Henneberg'' s Journal fiir Landwirt/iscJmft, 1866, pp. 289 to 297,) have ap- 
plied this method in the following manner : One part of the dry pulver- 
ized substance, (2 to 4 grams,) which has been previously extracted with 
water, alcohol, and ether, is placed in a glass-stoppered bottle, with 0.8 
part of chlorate of potash and 12 parts of nitric acid of specific gravity 
1.10, and digested at a temperature not exceeding 65° F. for 14 days. At 
the expiration of this time, the contents of the bottle are mixed with 
some water, brought upon a filter, and washed, firstly, with cold and 
afterwards, with hot water. When all the acid and soluble matters have 
been washed out, the contents of the filter are emptied into a beaker, 
and heated to 165° F. for about 45 minutes with weak ammonia, (1 part 
commercial ammonia to 50 parts of water) ; the substance is then brought 
upon a weighed filter, and washed, first, with dilute ammonia, as long as 
this passes off colored, then with cold and hot water, then with alcohol, 
and, finally, with ether. The substance remaining contains a small 
quantity of ash and nitrogen, for which corrections must be made. The 
fiber is, however, purer than that procured by the other method, and a 
somewhat larger quantity, ()^ to 13^ per cent,) is obtained. The results 
appear to vary but about one^e?" cent from the truth. 

The average proportions of cellulose found in various vegetable 
matters in the usual or air-dry state, are as follows : 



62 HOW CKOPS GROW. 

AMOUNT or CELLULOSE IN PLANTS. 

JPer cent. Per cetit. 

Potato tuber 1.1 Red clover plant in flower. . .10 

Wheat kernel 3.0 " " hay 34 

Wheat meal 0.7 Timothy " 23 

Maize kernel 5.5 Maize cobs. 38 

Barley " .,. 8.0 Oat straw 40 

Oat " 10.3 Wheat" 48 

Buckwheat kernel 15.0 Rye " 54 

Starch, G^^ H^o O^^. — The cells of the seeds of wheat, 
corn, and all other grains, and the tubers of the potato, 
contain this familiar body in great abundance. It occurs 
also in the wood of all forest trees, especially in autumn 
and winter. It accumulates in extraordinary quantity in 
the pith of some plants, as in the Sago-palm, {Metroxylon 
Humphii^ of the Malay Islands, a single tree of which 
may yield 800 lbs. 

Starch occurs in greater or less quantity in every plant 
that has been examined for it. 

The preparation of starch from the potato is very sim- 
ple. The potato contains, on the average, 76 per cent wa- 
ter, 20 per cent starch, and 1 per cent of cellulose, while 
the remaining 3 per cent consists mostly of matters which 
are easily soluble in water. By grating, the potatoes are 
reduced to a pulp ; the cells are thus broken and the starch- 
grains set at liberty. The pulp is then agitated on a fine 
sieve, in a stream of water. The washings run off milky, 
from suspended starch, while the cellulose is retained by 
the sieve. The milky fluid is allowed to rest in vats until 
the starch is deposited. It is then poured off, and the 
starch is collected and dried. 

Wheat-starch is commonly made by allowing wheaten 
flour mixed with water to ferment for several weeks. By 
this process the gluten, etc., are converted into soluble 
matters, which are removed by washing, from the unalter- 
ed starch. 

Starch is now largely manufactured from maize. A 



THE VOLATILE PART OF PLANTS. 63 

dilute solution of caustic soda is used to dissolve the al- 
buminoids, see p. 95. The starch and bran remaining, are 
separated by diffusing both in water, when the bran rap- 
idly settles, and the water being run off at the proper 
time, deposits the pure starch, corn-starch of commerce, 
also known as maizena. 

Starch is prepared by similar methods from rice, horse- 
chestnuts, and various other plants. 

Arrow-root is starch obtained by grating and washing 
the root-sprouts of Maranta Jndica, and M. arundinacea, 
plants native to the West Indies. 

Exp. 25. — Reduce a clean potato to pulp by means of a tin grater. 
Tie up. the pulp in a piece of not too fine muslin, and squeeze it repeat- 
edly in a quart or more of water. The starch grains thus pass the 
meshes of the cloth, while the cellulose is retained. Let the liquid stand 
until the starch settles, pour off the water, and dry the residue. 

Starch, as usually seen, is a white powder which con- 
sists of minute, rounded grains, and hence has a slightly 
harsh feel. When observed under a powerful magnifier, 
these grains often present characteristic forms and dimen- 
sions. 

In potato-starch they are G^g or kidney-shaped, and are 

J? c 




Fig. 12. 
distinctly marked with curved lines or ridges, which sur- 
round a point or eye ; a, fig. 12. Wheat-starch consists of 
grains shaped like a thick burning-glass, or spectacle-lens, 
having a cavity in the centre, h. Oat-starch is made up 
of compound grains, which are easily crushed into smaller 



64 HOW CROPS GROW. 

granules, e. lu maize and rice the grains are usually so 
densely packed in the cells as to present an angular (six- 
sided) outline, as in d. The starch of the bean and j)ea 
has the appearance of e. The minute starch-grains of the 
parsnip are represented at/*, and those of the beet at g, 

Tlie grains of potato-starch are among the largest, be- 
ing often l-300th of an inch in diameter ; wheat-starch 
grains are about 1-lOOOth of an inch ; those of rice, l-3000th 
of an inch, while those of the beet-root are still smaller. 

Unorganized Starch exists as a jelly in several plants, according to 
ScUeiden, {Botanik p. 137). Dragendorff asserts, that in the seeds of 
colza and mustard the starch does not occur in the form of grains, but 
in an unorganized state, which he considers to be the same as that no- 
ticed by Schleiden. 

The starch-grains are unacted upon by cold water, un- 
less broken, (see Exp. 26,) and quickly settle from suspen- 
sion in it. 

When starch is triturated for a long time with cold water, whereby the 
grains are broken, the liquid, after filtering or standing until perfectly 
clear, contains starch in extremely minute quantity. 

When starch is heated to near boiling with 12 to 15 times its weight 
of water, the grains swell and burst, or exfoliate, the water is absorbed, 
and the whole forms a jelly. This is the starch-paste used by the laun- 
dress for stifi"ening muslin. The starch is but very slightly dissolved b}' 
this treatment ; see Exp. 27. On freezing, it separates almost perfectly. 

When starch-paste is dried, it forms a hard, horn-like mass. 

Tapioca and Sago are starch, which, from being heated while still 
moist, is partially converted into starch-paste, and, on drying, acquires a 
more or less translucent aspect. Tapioca is obtained from the roots of 
the Ilanihot^ a plant which is cultivated in the West Indies and South 
America. Cassava is a preparation of the same starch, roasted. Sago is 
made in the islands of the East Indian Archipelago, from the pith of 
palms. It is granulated by forcing the paste through metallic sieves. 
Both tapioca and sago are now imitated from potato starch. 

Test for Starch. — The chemist is enabled to recognize 
starch with the greatest ease and certainty by its peculiar 
deportment towards iodine, which, when dissolved in wa- 
ter or alcohol and brought in contact with starch, gives 
it a beautiful purple or blue color. This test may be used 
even in microscopic observations with the utmost facility. 



THE VOLATILE PART OF PLANTS. 65 

Exp. 26. — Shake together in a test tube, 30 c. c. of water and starch 
of the bulk of a kernel of maize. Add solution of iodine, drop by drop, 
agitating until a faint purplish color appears. Pour off half the liquid 
into another test tube, and add at once to it one-fourth its bulk of iodine 
solution. The latter portion becomes intensely blue by transmitted, or 
almost black by reflected light. On standing, observe that in the first 
case, where starch preponderates, it settles to the bottom leaving a 
colorless liquid, which shows the insolubility of starch in cold water; 
the starch itself has a purple or red tint. In the case iodine was used in 
excess, the deposited starch is blue-black. 

Exp. 27. — Place a bit of starch as large as a grain of wheat in 30 c. c. 
of cold water and heat to boiling. The starch is converted into thin, 
translucent paste. That a portion is dissolved is shown by filtering 
through paper and adding to one-half of the filtrate a few drops of iodine 
solution, when a perfectly clear blue liquid is obtained. The delicacy 
of the reaction is shown by adding to 30 c. c. of water a little solution 
of iodine, and noting that a few drops of the solution of starch suffice to 
make the hirge mass of liquid perceptibly blue. 

By the prolonged action of dry heat, hot water, acids, 
or alkalies, starch is converted first into dextrin, and finally 
into sugar (glucose), as will be presently noticed. 

The same transformations are accomplished by the action 
of living yeast, and of the so-called diastase of germinat- 
ing seeds ; see p. 328. 

The saliva of man and plant-eating animals usually 
likewise dissolves starch at blood heat by converting it in- 
to sugar. It is much more promptly converted into sugar 
by the liquids of the large intestine. It is thus digested 
when eaten by animals. It is, in fact, one of the most im- 
portant ingredients of the food of man and domestic ani- 
mals. 

The action of saliva demonstrates that starch-grains are not homoge- 
neous, but contain a small proportion of matter not readily soluble in this 
liquid. This remains as a delicate skeleton after the grains are other- 
wise dissolved. It is probably cellulose. 

The chemical composition of starch is identical with 
that of cellulose ; see p. 60. 

Air-dry starch always contains a considerable amount 
of hygroscopic water, which usually ranges from 12 to 20 
per cent. 



66 HOW CEOPS GROW. 

Next to water and cellulose, starcli is the most abundant 
iDgredient of agricultural plants. 

In the subjoined taWe are given tlie proportions contained in certain 
vegetable products, as determined by Dr. Dragendorflf. The quantities 
are, however, somewhat variable. Since the figures below mostly refer 
to air-dry substances, the proportions of hygroscopic water are also 
given, the quantity of which being changeable must be taken into ac- 
count in making any strict comparisons. 

AMOUNT or STAKCH IN PLANTS. 

Water. Starch. 

Per cent. Per cent. 

Wheat 13.2 59.5 

Wheat flour 15.8 68.7 

Eye 11.0 59.7 

Oats 11.9 46.6 

Barley 11.5 57.5 

Timothy seed 12.6 45.0 

Kice (hulled) 13.3 61.7 

Peas.. 5.0 37.3 

Beans (white) 16.7 33.0 

Clover seed 10.8 10.8 

Flaxseed 7.6 23.4 

Mustard seed 8.5 9.9 

Colza seed 5.8 8.6 

TeltoAV turnips * dry substance 9.8 

Potatoes dry substance 62.5 

StarcJi 16 quantitatively estimated by various methods. 

1. In case of potatoes or cereal grains, it may be determined roughly 
by direct mechanical separation. For this purpose 5 to 20 grams of the 
substance are reduced to fine division by grating (potatoes) or by soften- 
ing in warm water, and crushing in a mortar (grains). The pulp thus 
obtained is washed either upon a fine hair-sieve or in a bag of muslin, 
until the water runs off clear. The starch is allowed to settle, dried, and 
weighed. The value of this method depends upon the care employed 
in the operations. The amount of starch falls out too low, because it is 
impossible to break open all the minute cells of the substance analyzed. 

2. In many cases starch may be estimated with more precision by con- 
version into sugar ; see p. 76. 

3. Dr. Dragendorflf, of the Rostock Laboratory, proceeds with starch de- 
terminations as follows : The pulverized substance, after drying out 
all hygroscopic moisture at 212°, is digested for 18 to 30 hours, at a tem- 
perature of 212°, in 10 to 12 times its weight of a solution of 5 to 6 parts 
of hydrate of potash in 94 to 95 parts of anhydrous alcohol. The 
digestion must take place in sealed glass tubes, or in a silver 
vessel which admits of closing perfect))'. By this treatment the 

* A sweet and mealy turnip grown on light soils for table use. 



THE VOLATILE PAET OF PLANTS. 67 

albiimiuoid substances, the fats, the sugar, and dextrin, are brought 
into such a condition that simple washing with alcohol or water suf- 
fices to remove them completely. The chief part of the phosphoric 
and silicic acids is likewise rendered soluble. The starch-grains 
are not afiected, neither does the cellulose undergo alteration, either 
qualitatively or quantitatively. In fact, this treatment serves excellently 
to isolate starch-grains for microscopic investigations. Besides starch 
and cellulose nothing resists the action of alcoholic potash save portions 
of cuticle, gum, and some earthy salts. 

When the digestion is finished, it is advisable, especially in case the 
substance is rich in fat, to bring the contents of the tube upon a filter 
while still hot, as otherwise potash-salts of the fatty acids may crystallize 
out. It is also well to wash immediately, first, with hot absolute alcohol, 
then, with cold alcohol of ordinary strength, and finally, with cold wa- 
ter until these several solvents remove nothing more. In the analysis 
of matters which contain much mucilage, as flaxseed, the washing 
must be completed with alcohol of 8 to 10 per cent, to prevent the 
swelling up of the residue. 

The filter should be of good ordinary (not Swedish) paper, should be 
washed with chlorhydric acid and water, dried at 212°, land weighed. 
When the substance is completely washed, the filter and its contents 
are dried, first at 120°, and finally at 212°. The loss consists of albumi- 
noids, fat, sugar, and a part of the salts of the substance, and when the 
last thi-ee are separately estimated, it may serve to control the estima- 
tion, by elementary analysis, of the albuminoids. 

The filter, with its contents, is now reduced to powder or shreds, and 
the whole is heated Avith water containing 5 per cent of chlorhydric 
acid until a drop of the liquid no longer reacts blue with iodine. The 
treatment with potash leaves the starch-grains in such a state of purity 
from incrusting matters, that their conversion into dextrin proceeds 
with great promptness, and is accomplished before the cellulose begins 
to be perceptibly acted upon. By weighing the residue that remains 
from the action of chlorhydric acid, after washing and drying, the 
amount of cellulose, cork, lignin, gum, and insoluble fixed matters is 
found. By subtracting these from the weight of the substance after 
exhaustion with potash, the quantity of starch is learned with great ac- 
curacy. The only error introduced by this method lies in the solution 
of some saline matters by the acid. The quantity is, however, so small 
as rarely to be appreciable. If needful, it can be taken into account by 
evaporating the acid solution to dryness, incinerating and weighing the 
residue. By warming with concentrated malt-extract at ]32°, the starch 
alone is taken into solution, and no correction is needed for saline mat- 
ters. If it is wished to determine the sugar produced by the transfor- 
mation of the starch, a weaker acid must of course be empl oyed. In case 
of mucilaginous substances, the starch must be extracted by digestion 
with a strong solution of chloride of sodium, with which the requisite 
quantity of chlorhydric acid has been mixed, and the residue should be 



68 HOW CKOPS GEOW. 

washed with water to which some alcohol has been added. — Henneberg's 
Jownal fiir Landioirthschaft, 1862, p. 206. 

Inulin, Cj2 H^^ O^^, closely resembles starch in many 
points, and appears to replace that body in the roots of 
the artichoke, elecampane, dahlia, dandelion, chicory, and 
other plants of the same natural family {compositce) . It 
may be obtained in the form of minute white grains, 
which dissolve easily in hot water, and mostly separate 
again as the water cools. Unlike starch, inulin exists in a 
liquid form in the roots above named, and separates in 
grains from the clear pressed juice when this is kept some 
time. According to Bouchardat, the juice of the dahlia 
tuber, expressed in winter, becomes a semi-solid white mass 
in this way, after reposing some hours, from the separa- 
tion of 8 per cent of this substance. 

Inulin, when pure, gives no coloration with iodine. It 
may be recognized in plants, where it occurs in a solution 
usually of the consistence of a thin oil, by soaking a slice 
of the plant in strong alcohol. Inulin is insoluble in this 
liquid, and under its influence shortly separates as a solid 
in the form of spherical granules, which may be identified 
with the aid of the microscope. 

When long boiled with water it is slowly but complete- 
ly converted into a kind of sugar, (levulose) ; hot dilute 
acids accomplish the same transformation in a short time. 
It is digested by animals, and doubtless has the same value 
for food as starch. 

In cJiemical composition^ inulin agrees perfectly with 
cellulose and starch ; see p. 60. 

Dextrin, C^^ ^10 ^105 ^^^ been thought to occur in small 
quantity dissolved in the sap of all plants. According to 
Von Bibra's late investigations,' the substance existing in 
breacl-grains w^hich earlier experimenters believed to be 
dextrin, is in reality gum. Busse, who has still more 
recently examined various young cereal plants and seeds, 



THE VOLATILE PAET OP PLANTS. 69 

and potato tubers, for dextrin, found it only in old potatoes 
and young wheat plants, and there in very small quantity. 
— Jahreshericht far Chemie^ 1866, p. 664. 

Dextrin is easily prepared artificially by the transforma- 
tion of starch, and its interest to us is chiefly due to this 
fact. When starch is exposed some hours to the heat of 
an oven, or 30 minutes to the temperature of 415° F., the 
grains swell, burst open, and are gradually converted into 
a light-brown substance, which dissolves readily in water, 
forming a clear, gummy solution. This is dextrin, and thus 
prepared it is largely used in the arts, especially in calico- 
printing, as a cheap substitute for gum arable, and bears 
the name British gum. In the baking of bread it is form- 
ed from the starch of the flour, and often constitutes ten 
per cent of the loaf. The glazing on the crust of bread, 
or upon biscuits that have been steamed, is chiefly due to 
a coatmg of dextrin. Dextrin is thus an important ingre- 
dient of those kinds of food which are prepared from the 
starchy grains by cooking. 

British gum, or commercial dextrin, appears either in 
translucent brown masses, or as a yellowish- white powder. 
On addition of cold water, the dextrin readily dissolves, 
leaving behind a portion of unaltered starch. When the 
solution is mixed with strong alcohol, the dextrin separates 
in white flocks, which, upon agitation, unite to translucent 
salvy clumps. With iodine, solution of commercial dex- 
trin gives a fine purplish-red color. Pure dextrin is, how- 
ever, unafiected by iodine. 

Exp. 28. — Cautiously heat a spoonful of powdered starch in a porce- 
lain dish, with constant stirring- so that it may not burn, for the space 
of five minutes ; it acquires a yellow, and later, a brown color. Now 
add thrice its bulk of water, and heat nearly to boiling. Observe that a 
Blimy solution is formed. Pour it upon a filter; the liquid that runs 
through contains dextrin. To a portion, add twice its bulk of alcohol ; 
dextrin is precipitated. To another portion, add solution of iodine ; this 
shows the presence of dissolved but unaltered starch, which likewise re- 
mains solid in considerable quantities upon the filter. To a third portion 



70 HOW CKOPS GROW. 

of the filtrate add one drop of strong sulplmric acid, and boil a few 
minutes. Test with iodine, which will now prove that all the starch is 
transformed. 

ISTot only heat, but likewise acids and ferments produce 
dextrin from starch, and also from cellulose. In the 
sprouting of seeds it is formed from starch, and hence is 
an ingredient of malt liquors. It is often contained in 
the animal body. Limpricht obtained nearly a pound of 
dextrin from 200 lbs. of the flesh of a young horse. — Ann. 
Ch. Ph., 133, p. 295. 

The chemical composition of dextrin is the same as that 
of cellulose, starch, and inulin. 

The Gums. — ^A number of bodies exist in the vegetable 
kingdom, which, from the similarity of their properties, 
have received the common designation of Gums. The 
best known are Gum Arabic, or Arabin y the gum of the 
Cherry and Plum, or Cerasin ; Gum Tragacanth and Bas- 
sora Gum, or JBassorin / and the Vegetable Mucilage of 
various roots, viz., of mallow and comfrey ; and of certain 
seeds, as those of flax and quince. 

Arabin t — Gum Arabic or Arabin exudes from the 
stems of various species Of acacia that grow in the tropi- 
cal countries of the East, especially in Arabia and Egypt. 
It occurs in tear-like, transparent, and, in its purest form, 
colorless masses. These dissolve easily in their own weight 
of water, forming a viscid liquid, or mucilage, which is em- 
ployed for causing adhesion between surfaces of paper, 
and for thickening colors in calico-printing. Gum Arabic, 
when burned, leaves about 3 per cent of ash, chiefly car- 
bonates of lime and potash ; it is, in fact, a compound of 
lime and potash with Arabic acid. 

Aral>ic Aciil is obtained pure by mixing a strong solution of gum 
Arabic with chlorhydric acid, and adding alcohol. It is thus pre- 
cipitated as a milk-white mass, whicl], when dried at 212°, becomes 
transparent, and has the composition C12 H22 On. 



THE VOLATILE PAET OF PLANTS. 



71 



In 100 parts, Araljic acid contains : 

Carlson 42.13 
Hydrogen 6.41 
Oxygen 51.47 



100.00 
By exposure to a temperature of 250°, Arabic acid loses one molecule 
of water, and becomes insoluble in water, being transformed into 
Ifetarahic Acid, (Fremy's Acid§ vietagummique). 

Cerasin. — ^The gum which frequently forms glassy- 
masses on the bark of cherry, plum, apricot, peach, and 
almond trees, is a mixture in variable proportions of 
Arabin, or the arabates of lime and potash, with cerasin, 
or the metarabates of lime and potash. Cold water dis- 
solves the former, while the cerasin remains undissolved, 
but swollen to a pasty mass or jelly. 

]?Ietaral>ic Acid, is prepared, as above stated, by exposing Arabic 
acid to a temperature of 250° F., and its composition is C12 H20 Oio- It 
is likewise produced by putting solution of gum Arabic in contact with 
oil of vitriol. On the other hand, metarabic acid is converted into Arabic 
acid, by boiling with water and a little lime or alkali. Metarabic acid, 
as well as its compounds with lime, potash, etc., are insoluble in water. 

BaSSOrin, C^^ H^^ 0^^, as found in Gum Tragacanth, has 
much similarity to metarabic acid in its properties, being 
insoluble in water, but swelling up in it to a paste or jelly. 

Vegetable Mucilage, C^^ H^o 0„, "^ 
has the same composition, and near- 
ly the same characters as Bassorin, 
and is possibly identical with it. It i^^^====nr=^^y=^^^^^==r^^ 
is an almost universal constituent p— ^-'^>-^-*^^-^-V— ^J 
of plants. 

It is procured in a state of purity by soak- 
ing unbroken flaxseed in cold water, with 
frequent agitation, heating the liquid to 
boiling, straining, and evaporating, until 
addition of alcohol separates tenacious ^^n W^^^0\ 
threads from it. It is then precipitated by 
alcohol containing a little cblorhydric -^'S- -'-^• 

acid, and washed by the same mixture. On drying, it forms a horny, 
colprless. and friable mass. Fig. 13 represents a highly magnified sec- 





.72 HOW CROPS GEOW. 

tion of the flaxseed. The external cells, a, contain the mucilage. "When 
soaked in water, the mucilage swells, bui'sts the cells, and exudes. 

One or other of these kinds of gum has been found in 
the following plants, viz., basswood, elm, apple, grape, 
castor-oil bean, mangold, tea, sunflower, pepper, in various 
sea-weeds, and in the seeds of wheat, rye, barley, oats, 
maize, rice, buckwheat, and millet. 

In the bread-grains, Arabin, or at least a soluble gum, 
occurs often in considerable proportion. 

TABLE OF THE PKOPOETIONS (per cent) OE GTJM IN VARIOUS AIR-DRY 
PLANTS OR PARTS OF PLANTS. 

{According to VonBibra, Die Getreidedrten mid das Brod.) 

Wheat kernel 4.50 

Wheat flour, superfine 6.25 

Spelt flour, {Triticum spelta^) 2.48 

Wheat bran 8.85 

Spelt bran 12.52 

Eye kernel 4.10 

Rye flour 7.25 

Rye bran 10.40 

Barley flour 6.33 

Barley bran 6.88 

Oat meal 8.50 

Rice flour 2.00 

Millet flour 10.60 

Maize meal 3.05 

Buckwheat flour 2.85 

The gums are converted into sugar by long boiling with 
dilute acids. 

The recent experiments of Grouven show that, contrary 
to what has been taught hitherto, gum, (at least gum 
Arabic,) is digestible by domestic animals. 

Saccharose or Cane Sugar, C,^ H^^ 0„, so called be- 
cause first and chiefly prepared from the 
sugar cane, is the ordinary sugar of com- 
merce. When pure, it is a white solid, 
readily soluble in water, forming a color- Fif.,i4. 

less, ropy, and intensely sweet solution. It crystallizes in 
rhombic prisms, fig. 14, which are usually small, as iu 



[\ 




~> 








\^ 




^^^ 



THE VOLATILE PART OF PLANTS. 73 

granulated sugar, but in tlie form of rock candy may be 
found an inch or more in length. The crystallized sugar 
obtained largely from the sugar-beet, in Europe, and that 
furnished in the United States by the sugar-maple and 
sorghum, when pure, are identical with cane-sugar. 

Saccharose also exists in the vernal juices of the walnut, 
birch, and other trees. It occurs in the stems of unripe 
maize, in the nectar of flowers, in fresh honey, in parsnips, 
turnips, carrots, parsley, sweet potatoes, in the stems and 
roots of grasses, and in a multitude of fruits. 

Exp. 29.— Heat cautiously a spoonful of white sugar uutil it melts, (at 
356" F.,) to a clear yellow liquid. On rapid cooliug, it gives a transpar- 
ent mass, known as harleTj sicgar, which is employed in confectionery. 
At a higher heat, it turns brown, frotlis, emits pungent vapors, and be- 
comes burnt sugar, or caramel, which is used for coloring soups, ale, etc. 

The quantity per cent o£ saccharose in the juice of various plants is 
given in the annexed table. It is, of course, variable, depending upon 
the variety of plant in case of cane, beet, and sorghum, as well as upon 
the stage of growth. 

SACCHAROSE IN TLANTS. 

2Jer cent. 

Sugar cane, average 18 Peligot 

Sugar beet, " 10 " 

Sorghum 9>^ Goessmann 

Maize, just flowered, 3% Ludersdorff 

Sugar maple, sap,average 2)4 Liebig 

Red maple, " " 2}4 " 

When a solution of this sugar is heated with dilute 
acids, or when acted on by yeast, it is converted into a mix- 
ture of equal parts of levulose, (fruit sugar,) and glucose, 
(grape sugar.) 

The composition of saccharose is the same as that of 
Arabic acid, and it contains in 100 parts : 
Carbon 42.11 
Plydrogen 6.43 
Oxygen 51.46 

100.00 
Lerulose, or Fruit Sugar, (Fructose,) C,, H,, O,,, exists 
mixed with other sugars in sweet fruits, honey, and mo- 
4 



74 now CEOPS geow. 

lasses. Inulin is converted into this sugar by long boil- 
ing with dilute acids, or with water alone. When pure, 
it is a colorless, amorphous* mass. It is incapable of crys- 
tallizing or granulating, and usually exists dissolved in a 
small proportion of water as a syrup. Its sweetness is 
equal to that of saccharose. 
Levulose contains in 100 parts : 

Carbon 40.00 

Hydrogen 6.67 

Oxygen 53.33 

100.00 

Glucose or Grape Sugar, C^, H^^ 0^„, naturally occurs 
associated with levulose in the juices of plants and in 
honey. Granules of glucose separate from the juice of the 
grape in drying, as may be seen in old " candied " raisins. 
Honey often granulates, or candies, on long keeping, from 
the crystallization of a part of its glucose. 

Glucose is formed from dextrin by the action of hot 
dilute acids, in the same way that levulose is produced 
from inulin. In the pure state it exists as minute, color- 
less crystals, and is, weight for weight, but half as sweet 
as the foregoing sugars. In composition it is identical 
with levulose. 

It combines chemically witli water in two proportions. Mono-hy- 
drated glucose, (C12 H24 O12 HoO,) or Antlion's liard crystallized grape- 
sugar, which is prepared in Germany by a secret process, is dry to the 
feel. Bi-hydrated glucose, (C12 H24 O12 2H2O,) occurs in commerce in an 
impure state as a soft, stick}', cr3'Stalline mass, which becomes doughy 
at a slightly elevated temperature. Both these hydrates lose their crystal- 
water at 212°. 

Dissolved in water, glucose yields a syrup, which is 

thin, and destitute of the ropiness of cane-sugar syrup. 

It does not crystallize, (granulate,) so readily as cane-sugar. 

Exp. 30.— Mis 100 c. c. of water with 30 drops of strong sulphuric 

acid, and heat to vigorous boiling in a glass flask. Stir 10 grams of 



* Literally Avithout shape, 1. e., not crj'stallized. 



THE VOLATILE PAKT OP PLANTS. 75 

starch witli a little water, and pour the mixture into the hot liquiil, drop 
by drop, so as not to interrupt the boiling. The starch dissolves, and 
passes first into dextrin, and finally into glucose. Continue the ebul- 
lition for several hours, replacing the evaporated water from time to 
time. To remove the sulphuric acid, add to the liquid, which may be 
still milky from impurities in the starch, powdered chalk, until the sour 
taste disappears ; filter from the sulphate of lime, (gypsum,) that is 
formed, and evaporate the solution of glucose* at a gentle heat to a 
syrupy consistence. On long standing it may crystallize or granulate. 

By this method is prepared the so-called potato-sugar, or starch-sugar 
of commerce, which is added to grape-juice for making a stronger wine, 
and is also emplojed to adulterate cane or beet-sugar. 

In the sprouting and malting of grain, glucosef is like- 
wise produced from starch. 

Even cellulose is convertible into glucose by the pro- 
longed action of hot dilute acids, and saw-dust has thus 
been made to yield an impure syrup, suitable for the pro- 
duction of alcohol. 

In the formation of glucose from cellulose, starch, and dextrin, the 
latter substances take up the elements of Avater as represented by the 
equation 

Starch, &c. Water. Glucose. 

Ci2 HoQ Oio + 3 H2O = C12 H24 C)i2 

In this process, 90 parts of starch, &c., yield 100 parts of glucose. 

Trommer''s Copper test. — A characteristic test for glucose and levulose 
is found in their deportment towards an alkaline solution of oxide of 
copper, which readily yields up oxygen to these sugars, being itself re- 
duced to yellow or red suboxide. 

Exp. 31.— Prepare the copper test by dissolving together in 30 c. c. of 
warm water a pinch of sulphate of copper and one of tartaric acid ; add 
to the liquid, solution of caustic potash until it feels slippery to the 
skin. Place in separate test tubes a few drops of solution of cane-sugar, 
a similar amount of the dextrin solution, obtained in Exp. 28 ; of solu- 
tion of glucose, from raisins, or from Exp. 30; and of molasses; add to 
each a little of the copper solution, and place them in a vessel of hot 



* If the boiling has been kept up hut an hour or so, the glucose will contain 
dextrin, as may he ascertamed by mixing a small portion of the still acid liqiud 
with 5 times its bulk of strong alcohol, which will precipitate dextrin, hut not 
ghicose. 

t According to^some authorities, the sugar of malt is distinct from glucose, 
and has been designated maltose. Probably, however, the so-called maltose is a 
mixture of glucose and dextrin. 



76 HOW CEOPS GROW. 

water. Observe that the saccliarose and dextrin suflfer no alteration for 
a lon<^ time, while the glucose and molasses shoi'tly eause the separation 
of suboxide of copper, 

Exp. 32. — Heat to boiling a little white cane-sugar with 30 e. c. of 
■water, and 3 drops of strong sulphuric acid, in a glass or porcelain dish, 
for 15 minutes, supplying the waste of water as needful, and test the 
liquid as in the last Exp. It will be found that this treatment trans- 
forms saccharose into glucose, (and levulose.) 

The quantitative estimation of the sugars and of starch is commonly 
based upon the reaction just described. Eor this purpose the alkaline 
copper solution is made of a known strength by dissolving a given weight 
of sulphate of copper, etc., in a given volume of water, and the glucose, 
or levulose, or a mixture of both, being likewise made to a known vol- 
ume of solution, it is allowed to flow slowly from a graduated tube into 
a measiired portion of warm copper solution, until the blue color is dis- 
charged. Experiment has demonstrated that one part of glucose or 
of levulose reduces 3.205 + parts of oxide of copper. Starch and sac- 
charose are first converted into glucose and levulose, by heating with an 
acid, and then examined in the same manner. For the details required 
to ensure accuracy, consult Fresenius' Quantitative Analysis. 

As already stated, cane-sugar, by long boiling of its 
aqueous solution, and under the influence of hot dilute 
acids (Exp. 32) and yeast, loses its property of ready crys- 
tallization, and is converted into levulose and glucose. 

According to Dubrunfaut, two molecules of cane-sugar take up the 
elements of two molecules, (5.26 per cent,) of water, yielding a mixture 
of equal parts of levulose and glucose. This change is expressed iu 
chemical symbols as follows : 

3 (Ci2 H22 On) + 3 H2O = C12 H24 O12 + Ci2 H24 O12 
Cane-sicgar. Water. Levulose. Ghicose. 

The alterability of saccharose on heating its solutions 
occasions a loss of one-third to one-half of what is really 
contained in cane-juice, and is one reason that solid sugar 
is obtained from the sorghum with such difiiculty. Mo- 
lasses, sorghum syrup, and honey, usually contain all three 
of these sugars. In molasses, both the saccharose and 
glucose are hindered from crystallization by the levulose, 
and by saline matters derived from the cane-jnice. 

Honey-dew, that sometimes fills in viscid drops from 
the leaves of the lime and other trees, is essentially a mix- 



THE VOLATILE PART OF PLANTS. 77 

ture of tlie three sugars with some gum. The mannas of 
Syria and Kurdistan are of similar composition. 

The older observers assumed the presence of gkicose in 
the bread grains. Thus Vauquelin found, or thought he 
found, 8.5°! of this sugar in Odessa wheat. More recent- 
ly, Peligot, Mitscherlich, and Stein have denied the pres- 
ence of any sugar in these grains. In his work on the 
Cereals and Bread, {Die Getreidearten und das Brod^ 
I860,) p. 163, Yon Bibra has reinvestigated this question, 
and found in fresh ground w^heat, etc., a sugar having 
some of the characters of saccharose, and others of glucose 
and levulose. It is, therefore, a mixture. 

Von Bibra found in tlie flour of various grains tlie following quan- 
tities of sugar, 

PROPORTIONS OF SUGAR IN AIR-DRY FLOUR, BRAN, AND MEAL. 

Ter cent. 

Wheat flour 2.33 

Spelt flour 1.41 

Wheat brau 4.30 

Spelt bran 2.70 

Rye flour 3.46 

Rye bran 1.86 

Barley meal 3.04 

Barley bran 1.90 

Oat meal 2.19 

Rice flour 0.39 

Millet flour 1.30 

Maize meal 3.71 

Buckwheat meal 0.91 

Glucosides. — There occur in the vegetable kingdom a 
large number of bodies, usually bitter in taste, which con- 
tain glucose, or a similar sugar, chemically combined 
with other substances, or yield it on decomposition. 
Tannin, the bitter principle of oak and hemlock bark ; 
salicin, from willow bark ; phloridzin, from the bark of 
the apple-tree root, and principles contained in jalap, 
scammony, the horse chestnut, and almond, are of this 
kind. The sugar may be obtained from these so-called 
glucosides by heating with dilute acids. 



78 " HOW CEOPS GEOW. 

Othe)' sugars. — Other su^-ars or saccliaroid bodies occurring in common 
or cultivated plants, but requiring no extended notice here, are the fol- 
lowing: — 

Mannite, Ce H34 Oe, is abuudant in tbe so-called manna of the apothe- 
cary, which exudes from the bark of several species of ash that grow in 
the Eastern Hemisphere, {Fraxinus ornus and rotundifolia.) It like- 
wise exists in the sap of our fruit trees, in edible mushrooms, and some- 
times is formed in the fermentation of sugar, (viscous fermentation.) 
It appears in minute colorless crystals, and has a sweetish taste. 

Querciie, Ce H12 O5, is the sweet principle of the acorn, from which it 
may be procured in colorless crystals. 

JRinite, Ce Hja O5, exudes from wounds in the bark of a Californian and 
Australian pine, {Plmis Lamhertiana.) Separated from the resin that 
usually accompanies it, it forms a white crystalline mass of a very sweet 
taste. 

Mycose, C12 H22 On, is a sugar found in ei-got of rye. It may be ob- 
tained in crystals, and is very sweet. 

Sugar of 3Iilk, Lactose., C12 H22 On + H2O, is the sweet principle of the 
milk of animals. It is largely prepared for commerce, in Switzerland, 
by evaporating whey, (milk from which casein and fat have been sepa- 
rated for making cheese.) In a state of purity, it forms transparent, col- 
orless crystals, which crackle under the teeth, and are but slightly sweet 
to the taste. When dissolved to saturation in water, it forms a sweet 
but thin syrup. 

Mutual transformations of the members of the Cellulose 
Group. — One of the most remarkable facts in the history 
of this group of bodies is the facility witb which its mem- 
bers undergo mutual conversion. Some of these changes 
liave been already noticed, but we may appropriately re- 
view them here. 

a. Transformations in the plant. — The machinery of the 
vegetable organism has the power to transform most, if 
not all, of these bodies into every other one, and Ave find 
nearly all of them in every individual of the higher order 
of plants in some one or other stage of its growth. 

In germination, the starch which is largely contained in 
seeds is converted into dextrin and glucose. It thereby 
acquires solubility, and jDasses into the embryo to feed the 
young plant. Here it is again solidified as cellulose, starch, 
or other organic principle, yielding, in fact, the chief part 
of the materials for the structure of the seedling. 



THE VOLATILE PART OF PLANTS. 79 

At spring-time, in cold climates, the starch stored up 
over winter in the new wood of many trees, especially the 
maple, appears to be converted into the saccharose which 
is found so abundantly in the sap, and this sugar, carried 
upwards to the buds, nourishes the young leaves, and is 
there transformed into cellulose, and into starch again. 

The sugar-beet root, when healthy, yields a juice con- 
taining 10 to 14 23er cent of saccharose, and is destitute of 
starch. Schacht has observed that in a certain diseased 
state of the beet, its sugar is partially converted into starch, 
grains of this substance making their appearance. ( Wil- 
da's CentralUatt, 1863, II, p. 217.) 

The analysis of the cereal grains sometimes reveals the 
presence of dextrin, at others of sugar or gum. 

Thus Stepf found no dextrin, but Iboth gum and sugar in maize-meal, 
{Jour, fur Prakt. Chem.^ 76, p. 92;) while Fresenius, in a more recent 
analysis, {Vs. St., 1, p. 180,) obtained dextrin, but neither sugar or gum. 
The sample of maize examined by Stepf contained 3.05 p. c. gum and 
3.71 p. c. sugar; that analyzed by Fresenius yielded 2.33 p. c. dextrin. 

Gum Tragacanth is a result of the transformation of 
cellulose, as Mohl has shown by its microscopic study. 

h. In the animal.^ the substances we have been describ- 
ing also suffer transformation when employed as food. 
During the process of digestion, cellulose, so far as it is 
acted upon, starch, dextrin, and probably the gums, are 
all converted into glucose. 

c. Many of these changes may also be produced apart 
from physiological agency, by the action of heat, acids, and 
ferments, operating singly or jointly. 

Cellulose and starch are converted by boiling wdth a 
dilute acid, into dextrin and finally into glucose. If paper 
or cotton be placed in contact with strong chlorhydric 
acid, (spirit of salt,) it is gradually converted into the 
same sugar. Cellulose and starch acted upon for some 
time by strong nitric acid, (aqua-fortis,) give compounds 
from which dextrin may be separated. Mtrocellulbse, 
(gun cotton,) sometimes yields gum by its spontaneous 



80 



HOW CROPS GROW. 



decomposition, (Hoffmann, Quart. Jour. Ghem. Soc, p. 
767.) A kind of gum also appears in solutions of cane- 
sugar or in beet-juice, when they ferment under certain 
conditions. Inulin and the gums yield sugar, (levulose,) 
but no dextrin, Avhen boiled with weak acids. 

d. It will be noticed that while physical and chemical 
agencies produce these metamorphoses in one direction, it 
is only under the influence of life that they can be accom- 
plished in the reverse manner. 

In the laboratory we can only reduce from a higher, 
organized, or more complex constitution to a lower and 
simpler one. In the vegetable, however, all these changes, 
and many more, take place with the greatest facility. 

The Chemical Composition of the Cellulose Group. — 
It is a remarkable fact that all the substances just de- 
scribed stand very closely related to each other in chemical 
composition, while several of them are identical in this 
respect. In the following table their composition is ex- 
pressed in formulae. 

CHEMICAL FORMULA OF THE BOT»IES OF THE CELLULOSE GROUP. 

Cellulose 

Starch 

Inulin 

Dextrin 

Bassorin I 

Ve<^. Miici]ae:e 

Metarabic acid J 

Arabic acid ) p tt r» 

^ \ ^12 •ti22 t»n 

Cane sugar ) 

Fruit sugar ) c,. H,, O,. 

Grape sugar ) 

It will be observed that all these bodies contain 12 
atoms of carbon, united to as much hydrogen and oxygen 
as form 10, 11, or 12 molecules of water. We can, there- 
fore, conceive of their conversion one into another, with 
no further change in chemical composition in any case, 
than the loss or gain of a few molecules of water. 



Ci2 H20 Cio 



THE VOLATILE PAET OF PLANTS. 81 

Isomerism. — Bodies which — like cellulose and dc-xtrln, or like levulose 
and glucose— are identical in composition, and 3'et are characterized by- 
different properties and modes of occurrence, are termed isomeric ; they 
are examples of isomerism. These words are of Greek derivation, and 
ei^mt J of equal measure. 

We must suppose that the particles of isomeric bodies which are com- 
posed of the same kinds of matter and in the same quantities, exist in 
different states of arrangement. Tlie mason can build from a given num- 
ber of bricks and a certain amount of mortar, a simple wall, an aqueduct, 
a bridge or a castle. The composition of these unlike structures may- 
be the same, both in kind and quantity; but the structures themselves 
differ immensclj'^, from the flict of the diverse arrangement of their ma- 
terials. In the same manner we may suppose starch to be converted 
into dextrin by a change in the relative positions of the atoms of carbon, 
hydrogen, and oxygen, which compose them. 

3. The Pectose Geoup. — The pectose group includes 
JPectose^ Pectin, PectosiG.^ Pectic, and Metapectic acids. 
These bodies exist in, or are derived from, fleshy fruits, 
including pumpkins and squashes, berries, the roots of 
the turnip, beet, onion, and. carrot, and in cabbage and. 
celery. They are an important part of the food of men 
and cattle. 

Pectose is the name given to a body which is supposed 
rather than demonstrated to occur with cellulose in the 
flesh of unripe fruits, and in the roots of turnips, carrots, 
and beets. Its characters in the pure state are as good as 
unknown, because we are as yet acquainted with no means 
of separating it from cellulose without changing its nature. 
Pectose is thought to constitute the chief bulk of the dry 
matter of the above-mentioned fruits and roots, and is con- 
cluded to be a distinct body by the products of its trans- 
formation, either such as are formed naturally, or those 
procured by artificial means. In what follows, we shall as- 
sume, with Fremy, {Ann. de Ghim. et de Phys., XXIY, 
6,) that pectose exists, and is the source of pectin, etc. 

Pectin is produced from pectose in a manner similar to 

that by which dextrin is obtained from cellulose or starch, 

viz., by the action of heat, of acids, and of ferments. When 

the flesh of fruits, or the roots which consist chiefly of 

4* 



82 HOW CROPS GROW. 

pectose, are subjected to the joint action of a moderate 
heat and an acid, the starch they contain is slowly altered 
into dextrin and sugar, while the firm pectose shortly soft- 
ens, becomes soluble in water, and is converted into pec- 
tin. It is 2:)recisely these changes which occur in the bak- 
ing of apples and pears, and in the boiling of turnips, car- 
rots, etc., with water. In the ripening of fruits the same 
transformation takes place. The firm pectose, under the 
influence of the acids that exist in all fruits, gradually soft- 
ens, and passes into pectin. 

Exp. 33. — Express, and, if turbid, filter tlirongli muslin the juice of a 
ripe apple, pear, or peacli. Add to the clear liquid its own bulk of al- 
cohol. Pectin is precipitated as a stringy, gelatinous mass, which, on 
drying, shrinks greatly in bulk, and forms, if pure, a white substance 
that may be easily reduced to powder, and is readily soluble in cold 
water. 

Exp. 34. — Reduce several Avhite turnips or beets to pulp by grating. 
Inclose the pulp in a piece of muslin, and wash by squeezing in water 
until all soluble matters are removed, or until the water comes off nenrly 
tasteless. Bring the washed pulp into a glass vessel, with enough dilute 
ehlorhydric acid, (1 part by bulk of commercial muriatic acid to 15 
parts of water,) to saturate the mass, and let it stand 48 hours. Squeeze 
out the acid liquid, filter it, and add alcohol, when pectin will separate. 

The strong aqueous solution of pectin is viscid or gummy, 
as seen in the juice that exudes from baked apples or pears. 

PcctOSic and Pcctic acids. — Under the action of a fer- 
ment occurring in many fruits, assisted by a gentle heat, 
pectin is transformed first into pectosic, and afterward into 
pectic acid. These bodies compose the well-known fruit- 
jellies. They are both insoluble in cold water, and remain 
suspended in it as a gelatinous mass. Pectosic acid is 
soluble in boiling water, and hence most fruit jellies be- 
come liquid when heated to boiling ; on cooling, its solu- 
tion gelatinizes again. Pectic acid is insoluble even in 
boiling water. It is formed also when the pulp of fruits 
or roots containing pectose is acted on by alkalies or by 
ammonia-oxide of copper. The latter agent, (a solvent 
of cellulose,) converts pectose directly into pectic acid, 



THE VOLATILE PAET OF PLANTS. 83 

wliich remains in insoluble combination with oxide of 
copper. 

Metapectic acid. — By too long boiling, by prolonged contact 
with acids or alkalies, and by deca}', the pectic and pcctosic acids, as well 
as pectin, are transformed into still another substance, viz., metapectic 
acid, which, according to Fremj'-, is a very soluble body of quite sour 
taste. It is the last product of the transformation of the bodies of this 
group with wliich we are acquainted. It exists, according to Fremy, in 
beet-molasses and decayed fruits. 

Exp. 35. — Stew a handful of sound cranberries, covered with water, 
just long enough to make them soft. Observe the speedy solution of 
the firm pectose. Strain through muslin. The juice contains soluble 
pectin, which may be precipitated from a small portion by alcohol. 
Keep the remaining juice heated to near the boiling point in a water 
bath, (i. e., by immersing the vessel containina: it in a larger one of boil- 
ing water.) After a time, which is variable according to the condition of 
the fruit, and must be ascertained by trial, the juice on cooling or stand- 
ing solidifies to a jelly, that dissolves on warming, and reappears again 
on cooling — Fremy's pcctosic acid. By further heating, the juice may 
form a jelly which is permanent when hot — pectic acid— and on still 
longer exposure to the same temperature, this jelly may dissolve again, 
by passing into Fremy's metapectic acid, which alcohol does not precip- 
itate. 

Other ripe fruits, as quinces, strawberries, peaches, grapes, apples, etc., 
may be employed for this expei'iment, but in any case the time required 
for the juice to run through these changes cannot be predicted safely, 
and the student may easily fail in attempting to follow them. 

Chemical composition of the Pectose group. — Our knowl- 
edge on this point is very imperfect. Pectose itself, hav- 
ing never been obtained pure, has not been analysed. The 
other bodies of this group have been examined, but, owing 
to the difficulty of obtaining them in a state of purity, the 
results of different observers are discordant. 
The formulge of Fremy are as follows : 

Pectose, 

Pectin, 

Pcctosic acid, 

Pectic acid, 

Metapectic acid, 

Grouven, {2ter Salzmunder Bericht^ p. 470,) has prepar- 
ed pectin on the large scale from beet-root cake, (remaining 
after the juice was expressed for sugar manufacture,) by 



unknown. 






C32 H40 O28 


+ 


4II20 


C16 H20 Oi4 


+ 


l^^HaO 


C16 H20 Oi4 


+ 


II20 


Cs Hio O7 


+ 


2 II2 



84 HOW CHOPS GEOW. 

digesting it with cold dilute chlorliydric acid, precipitat- 
ing and washing with alcohol. Thus obtained, it had all 
the characters ascribed to pectin. Its centesimal com- 
position, however, corresponded nearly with that assigned 
by Fremy to pectic acid, and differs somewhat from that 
given by this chemist for pectin, as is seen from the sub- 
joined figures; 

Pectin. Pectic acid. Orouveii' s pectin. 

C32 H48 O32 CiG H22 Oi5 

Carbon 40. 67 43. 29 43. 95 

Hydrogen 5.08 4.84 5.44 

Oxygen 54.25 53.87 51.61 

100.00 100.00 100.00 

From the best analyses and from analogy with cellulose 
it is probable that pectose has the same composition as 
pectin, or differs from it only by a few molecules of water. 
If we subtract the Avater, which in the formulae (p. 83) is 
separated by + from the remaining symbol, we see that 
the proj)ortions of Carbon, Hydrogen, and Oxygen are the 
same in all these bodies, and correspond to the formula 
Cg HjQ O,. This nearness of composition assists in com- 
prehending the ease with which the transformations of 
pectose into the other members of the group are effected. 

Relations of the Cellulose and Pectose Groups. — It was 
formerly thought that the pectin bodies are convertible 
into sugar by the prolonged action of acids. Fremy has 
shown that this is not the case. 

Sacc, {Ann. Ch. et Phys., 25, 218,) and Porter, {Aim. 
Oh. et Pharm.^ 71, 115,) have investigated a body having 
the properties and nearly the composition of pectic acid, 
which is produced by the action of nitric acid on wood. 

Divers, {Jour. Chem. jSoc, 1863, p. 91,) has observed 
a substance having the essential characters of pectic acid 
among the products of the spontaneous decomposition of 
nitrocellulose, (gun cotton.) 

It is probable, though not yet fairly demonstrated, 



THE VOLATILE PART OF PLANTS. 85 

that in the living plant cellulose passes into pectose and 
pectin. Without doubt, also, the reverse transformations 
may be readily accomplished* 

4. The Vegetable Acids. — The Vegetable Acids are 
very numerous. Some of them are found in all classes of 
plants, and nearly every family of the vegetable kingdom 
contains one or several acids peculiar to itself. Those 
^vhich concern us here are few in number, and though 
doubtless of the highest importance in the economy of 
vegetation, are of subordinate interest to the objects of 
this work, and will be noticed but briefly. They are 
oxalic^ tartaric^ malic, and citric acids. They occur in 
plants either in the free state, or as salts of lime, potash, 
etc. They are mostly found in fruits. 

Oxalic acid, C^ H^ O^ 2 H^ O, exists largely in the com- 
mon sorrel, and, according to the best 
obserA^ers, is found in greater or less 
quantity in nearly all plants. The pure 
acid presents itself in the form of color- 
less, brilliant, transparent crystals, not 
unlike Epsom salts in appearance, (Fig. °" * . 

15,) but having an intensely sour taste. 

Oxalic acid forms with lime a salt — the oxalate of lime 
— which is insoluble in pure water. It nevertheless exists 
dissolved in the cells of plants, so long as they are in active 
growtli, (Schmidt, Ann. Chem. u. Pharm., 61, 297.) To- 
wards the end of the period of growth, it often accumu- 
lates in such quantity as to separate in microscopic crystals. 
These are found in large quantity in the mature leaves and 
roots of the beet, in the root of garden rhubarb, and espe- 
cially in many lichens. 

Oxalate of potash is soluble in water, and exists in the 
juices of sorrel and garden rhubarb. It was formerly 
used for removing ink-stains from cloth and leather, under 
the name of salt of sorrel. Oxalic acid is now employed 
for this purpose. Oxalate of soda is soluble in water, and 



86 now CRors grow. 

is found in the juices of plants that grow on the sea-shore. 
Oxalate of ammonia is employed as a test for lime. 

Exp. 36.— Dissolve 5 grams of oxalic acid in 50 c. c. of hot water, add 
solution of ammonia or solid carbonate of ammonia until the odor of the 
latter slightly prevails, and allow the liquid to cool slowly. Long, needle- 
like crystals of a salt of oxalic acid and ammonia — the oxalate of ammonia 
—separate on cooling, the compound being sparingly soluble in cold wa- 
ter. Preserve for future use. , 

Exp. 37.— Add to any solution of lime, as lime-water, (see note, p. 36,) 
or hard well water, a few drops of oxalate of ammonia solution. Oxalate 
of lime immediately appears as a white powdery precipitate, which, from 
its extreme insolubility, serves to indicate the presence of the minutest 
quantities of lime. Add a few drops of chlorhydric or nitric acid to the 
oxalate of lime; it disappears. Hence oxalate of ammonia is a test for 
lime only in solutions containing no free mineral acid. (Acetic and 
oxalic acids, however, have little etfect upon the test.) 

Definition of Acids, JBases, and Salts. — In the popular 
sense, an acid is any body having a sour taste. It is, in 
fact, true that all sour substances are acids, but all acids 
are not sour, some being tasteless, others bitter, and some 
sweet. * A better characteristic of an acid is its capability 
of combining chemically with bases. The strongest acids, 
i. e. those bodies whose acid chai-acters are most strongly 
developed, if soluble, so as to have any eifect on the nerves 
of taste, are sour, viz., sulphuric acid, phosphoric acid, 
nitric acid, etc. 

Bases are the opposite of acids. The strongest bases, 
when soluble, are bitter and biting to the taste, and cor- 
rode the skin. Potash, soda, ammonia, and lime, are ex- 
amples. Magnesia, oxide of iron, and many other com- 
pounds of metals w^ith oxygen, are insoluble bases, and 
hence destitute of taste. Potash, soda, and ammonia, are 
termed alkalies ; lime and magnesia, alkali-earths. 

Salts are compounds of acids and bases, or at least re- 
sult from their chemical union. Thus, in Exp. 20, the salt, 
phosphate of lime, was produced by bringing together 
phosphoric acid, and the base, lime. In Exp. 37, oxalate 
of lime was made in a similar manner. Common salt — in 



THE VOLATILE PART OF PLANTS. 87 

chemical language, chloride of sodium — is formed when 

soda is mixed with chlorhydric acid, water being, in this 

case, produced at the same time. 

Teat for acids and alkalies. — Many vegetable colors are altered by solu- 
ble acids or soluble bases, (alkalies,) in such a manner as to answer the 
purpose of distinguishing these two classes of bodies. A solution of 
cochineal may be employed. It has a ruby-red color when concentrat- 
ed, but on mixing with much pure water, becomes orange or yellowish- 
orange. Acids do not affect tliis color, while alkalies turn it to an intense 
carmine or violet-carmine, which is restored to orange by acids. 

Exp. 38. — Prepare tincture* of cochineal by pulverizing 3 grams of 
cochineal, and shalcing frequently with a mixture of 50 c. c. of strong 
alcohol and 200 c. c. of water. After a day or two, pour off the clear 
liquid for use. 

To a cup of water add a few drops of strong sulphuric acid, and to an- 
other similar quautity add as many drops of ammonia. To the liquids 
add separately 5 drops of cochineal tincture, observing the coloration in 
each case. Divide the dilute ammonia into two portions, and pour into 
one of them the dilute acid, until the carmine color just passes into 
orange. Should excess of acid have been incautiously used, add ammo- 
nia, until the carmine reappears, and destroy it again by new portions 
of acid, added dropwise. The acid and base thus neutralize each other, and 
the solution contains sulphate of ammonia, but no free acid or base. It 
will be found that the orange-cochineal indicates very minute quantities 
of ammonia, and the carmine-cochineal correspondingly small quantities 
of acid. Tincture of litmus, (procurable of the apothecary,) or of dried 
red cabbage, may also be employed. Litmus is made red by soluble 
acids, and blue by soluble bases. With red cabbage, acids develope a 
purple, and the bases a green color. 

In the formation of salts, the acids and bases more or less neutralize 
each other'' s properties, and their compounds, when soluble, have a less 
sour or less acrid taste, and act less vigorously on vegetable colors than 
the acids or bases themselves. Some soluble salts have no taste at all 
resembling either their base or acid, and have no effect on vegetable col- 
ors. This is true of common salt, glauber salts or sulphate of soda, and 
saltpeter or nitrate of potash. Others exhibit the properties of their 
base, though in a reduced degree. Carbonate of ammonia, for example, 
has much of the odor, taste, and effect on vegetable colors that belong 
to ammonia/. Carbonate of soda has the taste and other properties of 
caustic soda in a greatly mitigated form. On the other hand, suli^hates of 
alumina, iron, and copper, have slightly acid characters. 

Certain acids form with the same base several distinct salts. Thus 
carbonic acid and soda may produce carbonate of soda, Na20 CO2, or 



* Tinctures, In the langiiago of the apothecary, arc alcoholic solutions. 



88 HOW CROPS GKOW. 

bicarbonate of soda, Na H CO2. The latter is mueh less allv'aline than 
the former, but both turn cochineal to a carmine color. Again, phos- 
phoi'ic acid may form three distinct salts with soda or with lime, which 
will be noticed in another place. Oxalic acid also yields several kinds 
of salts, as do the other organic acids presently to be described. 

Malic acidj C^ H^ 0^., is the chief sour principle of ap- 
ples, currants, gooseberries, plums, cherries, strawberries, 
and most common fruits. It exists in small quantity in a 
multitude of plants. It is found abundantly in combina- 
tion with potash, in the garden rhubarb, and malate of 
potash may be obtained in crystals by simj^ly evaporating 
the juice of the leaf-stalks of this plant. It is likewise 
abundant as lime-salt in the nearly ripe berries of the 
mountain ash, and in barberries. Malate of lime also 
occurs in considerable quantity in the leaves of tobacco, 
and is often encountered in the manufacture of maple su- 
gar, separating as a white or gray sandy powder during 
the eva^Doration of the sap. 

Pure malic acid is only seen in the chemical laboratory, 
and presents white, crystalline masses of an intensely sour 
taste. It is extremely soluble in water. 

Tartaric acid, C^ H^ O^, is abundant in the grape, from 
the juice of which, during fermentation, it is deposited in 
combination with potash as argol. This, 
on purification, yields the cream of tartar, 
(bitartrate of potash,) of commerce. Tar- 
trates of potash or lime exist in small 
quantities in tamarinds, in the unripe bcr- Fig. 10. 

ries of the mountain ash, in the berries of the sumach, in 
cucumbers, potatoes, pine-a2:)ples, and many other fruits. 
The acid itself may be obtained in large glassy crystals, 
(see Fig. 16,) which are very sour to the taste. 

Citric acid, C^ Hg O,, exists in the free state in the juice 
of the lemon, and in unripe tomatoes. It accompanies 
malic acid in the currant, gooseberry, cherry, strawberry, 
and raspberry. It is found in email quantity, imitcd to 




THE VOLATILE PAET OF PLANTS. 89 

lime, in tobacco leaves, in the tubers of the Jerusalem 
artichoke, in the bulbs of onions, in beet roots, in coffee- 
berries, and in the needles of the fir tree. 

In the pure state, citric acid forms large transparent 
or white crystals, very sour to the taste. 

Melations of the Vegetable Adds to each other and to the Amyloids. — The 
four acids above noticed usually occur together in our ordinary fruits, 
and it appears that some of them undergo mutual conversion in the liv- 
ing plant. 

According to Liebig, the unripe berries of the mountain ash contain 
much tartaric acid, which, as the fruit ripens, is converted into malic 
acid. Schmidt, {Anv. Chem. u. Pharm., 114, 109,) first showed that tar- 
taric acid can be artificially transformed into malic acid. The chemical 
change consists merely in the removal of one atom of oxygen. 
Tartaric acid. Malic acid. 
C4 He Oe — O = C4 He O5 

When citric, malic, and tartaric acids are boiled -with nitric acid, or 
heated with caustic potash, they all yield oxalic acid. 

Cellulose, starch, dextrin, the sugars, and, according to some, pectic 
acid, yield oxalic acid, when heated with potash or nitric acid. Com- 
mercial oxalic acid is thus made from starch and from saw-dust. 

Gum (Arabic,) sugar, starch, and, according to some, pectin, yield tar- 
taric acid by the action of nitric acid. 

5. Fats and Oils (Wax). — Wq have only space here 
to notice this important class of bodies in a very general 
manner. In all plants and nearly all parts of plants 
we find some representatives of this group; but it is 
chiefly in certain seeds that they occur most abundantly. 
Thus the seeds of hemp, flax, colza, cotton, bayberry, 
pea-nut, butternut, beech, hickory, almond, sunflower, 
etc., contain 10 to 70 per cent of oil, which may be ia 
great part removed by pressure. In some plants, as the 
common bayberry, and the tallow-tree of iN'icaragua, the 
fat is solid at ordinary temperatures, and must be extracted 
by aid of heat ; while, in most cases, the fatty matter is 
liquid. The cereal grains, especially oats and maize, con- 
tain oil in appreciable quantity. The mode of occurrence 
of oil in plants is shown in fig. 17, which represents a 
highly magnified section of the flax-seed. The oil exists 



90 



HOW CROPS GROW. 




OOOOOI 




Fio;. 17. 



as minute, transparent globules in the cells, f. From 
these seeds the oil may be completely extracted by ether, 
benzine, or sulphide of carbon, 
which dissolve all fats with readi- 
ness," but' scarcely affect the other 
vegetable principles. 

Many plants yield small quan- 
tities of wax, which either gives a 
glossy coat to their leaves, or 
forms a bloom upon their fruit. 
The lower leaves of the oat plant 
at the time of blossom contain, in 
the dry state, 10 j)er cent of fat 
and wax, (Arendt) . Scarcely two 
of these oils, fats, or kinds of wax, are exactly alike in 
their properties. They differ more or less in taste, odor, 
and consistency, as well as in their chemical composition. 

Exp. 39— Place a handful of fine and fresh corn or oat meal which has 
been dried for an hour or so at a heat not exceeding 213°, in a bottle. 
Pour on twice its bulk of ether, cork tightly, and agitate frequently for 
half an hour. Drain otf the liquid (filter, if need be) into a clean porce- 
lain dish, and allow the ether to evaporate. A yellowish oil remains, 
which, by gently warming for some time, loses the smell of ether and 
becomes quite pure. 

The fatty oils must not be confounded with the ethereal^ 
essential, or volatile oils. The former do not evaporate 
except at a high temperature, and when brought upon 
paper leave a permanent " grease-spot." The latter readily 
volatilize, leaving no trace of their presence. The former, 
when pure, are without smell or taste. The latter usually 
possess marked odors, which adapt many of them to use 
as perfumes. 

In the animal body, fat (in some insects, wax,) is formed 
or appropriated from the food, and accumulates in consid- 
erable quantities. How to feed an animal so as to cause 
the most rapid and economical fattening is one of the 
most important questions of agricultural chemistry. 



i 



THE VOLATILE PART OF PLANTS. 91 

Plowcvcr greatly the various fats may differ in external 
characters, they are all mixtures of a few elementary fats. 
The most abundant and commonly occurring fats, espe- 
cially those which are ingredients of the food of man and 
domestic animals, viz. : tallow, olive oil, and butter, con- 
sist essentially of three substances, which we may briefly 
notice. These elementary fats are Stearin^ Palmlt'm^ and 
Olein^ and they consist of carbon, oxygen, and hydrogen, 
the first-named element being greatly preponderant. 

Stearin is represented by the formula C^^ IT„„ 0„. It 
is the most abundant ingredient of the common fats, and 
exists in largest proportion in the harder kinds of tallow. 

ExL', 40. — Ilcat mutton or hccf tallow, in ;i l)ottle tliat may l)o ti^'litly 
corked, with ten times its bulk of coneentrated ether, until a elear solu- 
tion is obtained. Let cool slowly, when stearin will crystallize out in 
pearly scales. 

Palmitin, C^, IT^^ O,,, receives its name from the palm 
oil, of Africa, in which it is a large ingredient. It 
forms a good i)art of bntter, and is one of the chief con- 
stituents of bees-wax, and of bayberry tallow. 

Oleill, C;.^ II, J,, 0,„ is the liquid ingredient of fats, and 
occurs most abundantly in the oils. It is prepared from 
olive oil by cooling down to the freezing point, when the 
stearin and palmitin solidify, leaving the olein still in the 
liquid state. 

Other elementary fats, viz.: butyrin, laurln, myristin, ete., occur in 
small quantity in butter, and in various vegetable oils. Flaxseed oil 
contains liuolein ; castor oil, ricinolein, etc. 

We have already given the formuhie of the princijial 
fats, but for our purposes, a better idea of their composi- 
tion may be gathered from a centesimal statement, viz. : 



* Margarin, formerly thought to bo a distinct fut, is a mixture of stearin and 
palmitiu. 



92 HOW CKOPS GROW. 

CElin'ESIMAL COMPOSITION OP THE ELEMENTARY FATS. 

Stearin. JPahnitin. Olein. 

Carbon, 76.6 75.9 - 77.4 

Hydrogen, 12.4 12.2 11.8 

Oxygen, 10.0 11.9 10.8 



100.0 100.0 100.0 

PJiosphorized Fats. — The animal brain and spinal cord, 
and the yolk of the Qg^, contain a considerable amount of 
fat which has long been characterized by a small con- 
tent of phosphorus. Yon Bibra found the quantity of 
phosphorus in this (impure) fat to range from 1.21 to 2.53 
per cent. Knop ( Ys. St. 1, p. 26) was the first to show that 
analogous phosphorized fats exist in plants. From the 
sugar pea he extracted 2.5 per cent of a thick brown oil, 
which Avas free from sulphur and nitrogen, but contained 
1.25 per cent of phosphorus. 
The composition of this oil was as follows : 

Carbon 66.85 

Hydrogen 9.53 

Oxygen 22.38 

Phosphorus 1.25 

100.00 
Topler {Senneberg's Jahreshericht 1859—1860, p. 164) 
subsequently examined the oils of a large number of seeds 
for phosphorus with the subjoined results : 

Source of Per cent of 
fat. p7ios2)7iorus. 
Walnut trace 



Source of Per cent of 

fat. phosphorus^. 

Lupine 0.29 

Pea 1.17 

Horse bean 0.72 

Vetcli 0.50 

Winter lentil 0.39 

Horse-chestnut 0.30 

Chocolate bean none 

Millet " 

Poppy " 



Olive none 

Wheat 0.25 

Barley 0.28 

Rye 0.31 

Oat 0.44 

Flax none 

Colza " 

Mustard " 



THE VOLATILE PAET OF PLANTS. 93 

According to Hoppe-Seyler, {lied. CJiem. Unters., I,) the pliosphorized 
principle of oil of maize, and of the brain, nerves, yolk of eggs, etc., is 
primarily the substance discovered in 1864 by Liebreich, in the brain, 
and termed Protag-on. It is a white crystallized body, having the 
following composition : 

Carbon, 67.2 

Hydrogen, 11.6 

Nitrogen, 2.7 

Phosphorus, 1.5 

Oxygen, 17.0 



100.0 
Its formula is Cue, H241, N4, P, O22. When heated to the boiling point 
it is decomposed, and yields among other products glycerin, phosphor- 
ic acid, and stearic acid. {Ann. Ch. Fh., 134, p. 30). 

/Saponification. — The fats are characterized by formmg 
soaps when heated with strong potash or soda-lye. They 
are by this means decomposed, and give rise to fatt^ 
acids, which remain combined with the alkalies, and glyce- 
rin., a kind of liquid sugar. 

Exp. 41.— Heat a bit of tallow with strong solution of caustic potash 
until it completely disappears, and a soap, soluble in water, is obtained. 
To one-half the hot solution of soap, add chlorhydric acid until the 
latter predominates. An oil will separate which gathers at the top of 
the liquid, and on cooling, solidifies to a cake. This is not, how^ever, 
the original fit. It has a different melting point, and a diflferent chemi- 
cal composition. It is composed of one or several fatty acids, corre- 
sponding to the elementary fats from which it was produced. 

When saponified by the action of potash, stearin yields 
stearic acid^Q^^ H^gOj; palmitin jieldi^ palmitic acid, 
Cjg H32 O2 ; and olein gives oleic acid, C^g Hg^ O^. The 
so-called stearin candles are a mixture of stearic and 
palmitic acids. The glycerin, C3 Hg O3, that is simulta- 
neously produced, remains dissolved in the liquid. Glyce- 
rin is now found in commerce in a nearly pure state, as a 
colorless, syrupy liquid, having a pleasant sweet taste. 

The chemical act of saponification consists in the re-arrangement 
of the elements of one molecule of fat and three molecules of water in- 
to three molecules of fatty acid, and one molecule of glycerin. 

Palmitin Water. Palmitic acid. Glycerin. 

C51 H98 Oe -h 3 (Ha 0) =» 3 (C16 H32 O2) + C3 Hs Os. 



94 HOW CROPS GKOW. 

Saponification is likewise eflfected by tlie influence of strong acids and 
by lieatiDg with water alone to a temperature of near 400° F. 

Ordinary soap is nothing more than a mixture of stearate, palmitate, 
and oleate of potash of soda, with or without glycerin. Common soft 
soap consists of the potash-compounds of the above-named .acids, mixed 
with glycerin and water. Hard soap is usually the corresponding 
soda-compound, free from glycerin. When soft potash-soap is boiled 
with common salt (chloride of sodium), hard soda-soap and chloride of 
])otassium are formed by transposition of the ingredients. On cooling, 
soda-soap foi-ms a solid cake upon the liquid, and the glycerin remains 
dissolved in the latter. 

Melations of Fats to Amyloids. — The oil or fat of 
plants is in many cases a product of the transformation of 
starch or other member of the ceUulose group, for the oily 
seeds, when immature, contain starch, which vanislies as 
they ripen, and in the sugar-cane the quantity of wax is 
said to be largest when the sugar is least abundant, and 
vice versa. In germination the oil of the seed is con- 
verted back again into starch, sugar, etc. 

The Edlmaiion of Fat (including wax) is made by warming the pulver- 
ized and dry substance repeatedly with renewed quantities of ether, or 
sulphide of carbon, as long as the solvent takes up anything. On evap- 
orating the solutions, the fat remains nearly in a state of purity, and 
after drying thoroughly, may be weighed. 

PROPORTIONS OF TAT IN VARIOUS VEGETABLE PRODUCTS. 
Fer cent. 

Meadow grass 0.8 

Ked clover (green) 0.7 

Cabbage 0.4 

Meadow hay 3.0 

Clover hay 3.2 

Wheat straw 1.5 

Oat straw 2.0 

Wheat bran 1.5 

Potato tuber 0.3 

6. The Albuminoids or Protein Bodies. — ^The bodies 
of this class differ from the groups hitherto noticed in 
the fact of their containing in addition to carbon, oxygen, 
and hydrogen, 15 to 18 per cent of nitrogen., with a small 
quantity of sulphur, and, in some cases, phosphorus. 



Turnip . . 


Fer cent. 
01 


Wheat kernel 

Oat " 


1.6 

1.6 


Maize " 


... 70 


Pea " ... 


30 


Cotton seed 

Flax 

Colza " 


34.0 

34.0 

45.0 



THE VOLATILE PART OP PLANTS. 95 

In plants, the Protein Bodies occur in a variety of modi- 
fications, and though found in small proportion in all their 
parts, being everywhere necessary to growth, they are 
chiefly accumulated in the seeds, especially in those of 
the cereal and leguminous grains. 

The albuminoids^ as we shall designate them, that oc- 
cur in plants, are so similar in many characters, are, in 
fact, so nearly identical with the albuminoids which con- 
stitute a large portion of every animal organism, that we 
may advantageously consider them in connection. 

We may describe the most of these bodies under three 
sub-groups. The "type of the first is albumin, or the 
white of Qgg', of the second, ^5rm, or animal muscle; of 
the third, casein, or the curd of milk. 

Common Characters. — The greater number of these 
substances occur in several, at least two, modifications, 
one soluble, the other insoluble in water. 

In living or undecayed animals and plants we find the 
albuminoids in the soluble, and, in fact, in the dissolved 
state. They may be obtained in the solid form by evap- 
orating off at a gentle heat the water which is naturally 
associated with them. They are thus mostly obtained as 
transparent, colorless or yellowish solids, destitute of odor 
or taste, which dissolve again in water, but are insoluble 
in alcohol. 

Kecently, both m the animal and vegetable, soluble al- 
buminoids have been observed in colorless or red crystals, 
(or crystalloids,) often of considerable size, but so asso- 
ciated with other bodies as, in general, not to admit of sep- 
aration in the pure state. 

The insoluble album^inoids, some of which also occur- 
naturally in plants and animals, are, when purified as much 
as possible, white, flocky, lumpy or fibrous bodies, quite 
odorless and tasteless. 

As further regards the deportment of the albuminoids towards sol- 
vents, some are dissolved in alcohol, none in ether. They are soluble in 



96 HOW CEOPS GEOW. 

potash and soda-13'e; acids separate them from these solutions, strong 
acetic acid dissolves them with one exception. In ver}^ dilute mineral 
acids (sulphuric and chlorh3'dric) some of them dissolve in great part, 
others swell up like jelly. 

Coagulation. — A remarkable characteristic of the group 
of bodies now under notice is their ready conversion from 
the soluble to the insoluble state. In some cases this 
coagulation happens spontaneously, in others by elevation 
of temperature, or by contact with acids, metallic oxides, 
or various salts. 

The albuminoids, when subjected to heat, melt and bum 
with a smoky flame and a peculiar odor — that of burnt- 
hair or horn, — while a shining charcoal remains which is 
difficult to consume. 

Tests for tlie All>iiMii]nLoid.s.— The chemist employs the 
behavior of the albuminoids tow^ards a number of reagents * as tests 
for their presence. Some of these are so delicate and characteristic as 
to allow the distinction of this class of substances from all others, even 
in microscoiDic observations. 

1. Iodine colors them intensely yellow or bronze. 

2. Warm and'strong ddorhyclHc acid colors all these bodies blue or 
violet, or, if applied in large excess, dissolves them to a liquid of these 
colors, 

3. In contact with oiitric acid they are stained a deep and vivid yellow. 
Silk and wool, which consist of bodies closely approaching the albumin- 
oids in composition, are commonly dyed or printed yellow by means of 
nitric acid. 

4. A solution of 7iitrate of mercury in excess of nitric acid, t tinges 
them of a deep red color. This test enables us to detect albumin, for 
example, even where it is dissolved in 100,000 parts of water. 

Albumin* — Animal Albumin. — The white of a hen's 
e^^ on drying yields about 12 per cent of albumin in a 
state of tolerable purity. The fresh white of Qgg serves 



* Eeagents are substances commonly employed for the recognition of 
bodies, or, generally, to produce chemical changes. All chemical phenomena re- 
sult from the mutual action of at least two elements, which thus act and react on 
each other. Hence the substance that excites chemical changes is termed a re- 
agent, and the phenomena or results of its application are cahed reactions. 

t This solution, known as Millon's test, is prepared by dissolving mercury 
in its own weight of nitric acid of sp. gr. 1.4, heating towa,rd3 the close of the 
process, and finally adding to the liquid twice its bulk of water. 



THE VOLATILE PART OF PLANTS. 97 

to illustrate the peculiarities of this substance, and to ex- 
hibit the deportment of the albuminoids generally towards 
the above-named reagents. 

Ext. 43. — Beat or wliip the white of an egg so as to destroy the deli- 
cate transparent membrane in the cells of which the albumin is held, 
and agitate a portion of it with water ; observe that it dissolves readily in 
the latter. 

Exp. 43.— Heat a part of the undiluted white of egg in a tube or cup 
atl65° F.; it becomes opaque, white, and solid, (coagulates) and is convert- 
ed into the insoluble modification. A hidier heat is needful to coagulate 
solutions of albumin, in-proportion as they are diluted with water. 

Exp. 44. — Add strong alcohol to a portion of the solution of albumin 
of Exp. 43. It produces coagulation. 

Exp. 45.— Observe that albumin is coagulated by dilute acids applied 
in small quantity, especially by nitric acid. 

Exp. 46. — Put a little albumin, either soluble or coagulated, into each 
of four test tubes. To one, add solution of iodine ; to a second, strong 
chlorhydric acid ; to a third, nitric acid ; and to the last, nitrate of 
mercury. Observe the characteristic colorations that appear immedi- 
ately, or after a time, as described above. In the last three cases the 
reaction is hastened by a gentle heat. 

Albumin occurs in the soluble form in the blood, and in 
all the liquids of the healthy animal body except the urine. 
In some cases its characters are slightly different from 
those of egg-albumin. The albumin of the blood, which 
may bg separated by heating blood-serum (the clear 
yellow liquid that floats above the clot), contains a little 
less sulphur than coagulated egg-albumin. In the crystal- 
line lens of the eye, and in the blood corpuscles, the al- 
bumin has again slightly different characters, and has been 
termed glohuUn. Under certain conditions the blood of 
animals yields a substance known as hmmoglohin^ which, 
while having nearly the composition and many of the 
properties of albumin, commonly requires a much larger 
proportion of water for solution, and forms distinct crys- 
tals of a transparent red color. 

Vegetable Albumin. — In the juices of all plants is found 
a minute quantity of a substance which agrees in nearly 
all respects with animal albumin, and' is hence termed 
5 



98 HOW CROPS GEOW. 

vegetable aTbumin. The clear juice of tlie potato tuber 
(which may be procured by grating potatoes, squeezing 
the pulp in a cloth, and letting the liquor thus obtained 
stand in a cool place until the starch has deposited,) con- 
tains albumin in solution, as may be shown by heating to 
near the boiling point, when a coagulum separates, which, 
after boiling successively with alcohol and ether to remove 
fat and coloring matters, is scarcely to be distinguished, 
either in its chemical reactions or composition from the 
coagulated albumin of eggs. 

The juice of succulent vegetables, as cabbage, yields 
vegetable albumin in larger quantity, though less pure, by 
the same treatment. 

Water which has been agitated for some time in contact 
with flour of wheat, rye, oats, or barley, is found by the 
same method to have extracted albumin from these grains. 

The coagulum, thus pi-epared from any of these sources, exhibits the 
reactions characteristic of the albuminoids, when put in contact with 
nitrate of mercury, nitric or chlorhydric acids. 

Exp. 47. — Prepare impure vegetable albumin from potatoes, cabbage, 
or flour, as above described, and apply the nitrate of mercury test. 

Fibrin* — IBlood-Fibrin. — The blood of the higher ani- 
mals, when in the body or when fresh drawn, is perfectly 
fluid. Shortly after it is taken from the veins it partially 
solidifies — it coagulates or becomes clotted. It hereby 
separates into two portions, a clear, pale-yellow liquid — 
the serum, and the clot. As already stated, the serum 
contains albumin. The clot consists chiefly of fibrin. On 
squeezing and washing the clot with water, the coloring 
matter of the blood is removed, and a white stringy mass 
remains, which is one form of the substance in question. 
Blood-fibrin is not known in the soluble state, except in 
jfresh blood, from which it cannot be separated, as it so 
soon coagulates spontaneously. 

Prepared as just described, fibrin has many of the proper- 
ties of albumin. Placed in a solution of saltpeter, espe- 



THE VOLATILE PAET OF PLANTS, 99 

cially if a little potash lye be added, it dissolves in a few 
days to a clear liquid, which coagulates on heating or by 
addition of metallic salts, in the same manner as a solu- 
tion of albumin. In very dilute chlorhydric acid, it swells 
up, but does not dissolve. 

Exp. 48.— Observe the eeparation of blood into clot and serum ; co- 
agulate tlie albumin of the former by heat, and test it with warm chlor- 
hydric acid. Tie up the clot in a piece of muslin, and squeeze and wash 
in water until coloring matter ceases to run off. Warm it with nitric 
acid as a test. 

Flesh-Jlhrin. — If a piece of lean beef or other meat be 
repeatedly squeezed and washed in water, the coloring 
matters are gradually removed, and a white residue is ob- 
tained, which resembles blood-fibrin in its external char- 
acters. It is, in fact, the actual fibers of the animal muscle, 
and hence its name. It is characterized by dissolving in 
very dilute chlorhydric acid, (one part acid and 1,000 of 
water) to a clear liquid, from which it is again separated 
by careful addition of an alkali, or a solution of common 
salt. 

Vegetahle-fibrin, — ^When wheat-flour is mixed with a 
little water to a thick dough, and this is washed and 
kneaded for some time in a vessel of water, the starch and 
albumin are mostly removed, and a yellowish, tenacious 
mass remains, which bears the name gluten. When wheat 
is slowly chewed, the saliva carries off the starch and other 
matters, and the gluten mixed with bran is left behind — 
well-known to country lads as " wheat-gum." 

Exp. 49.— Wet a handful of good, fresh, wheat flour slowly with a lit- 
tle water to a sticky dough, and squeeze this under a fine stream of 
water until the latter runs off clear. Heat a portion of this gluten with 
Millon's test. 

Gluten is a mixture of several albuminoids, and contains 

besides some starch and fat. Vegetable-fibrin is dissolved 

from it by alcohol, and separates on removing the alcohol 

by evaporation. 

The albuminoids of crude gluten dissolve in very dilute potash-lye, 



100 HOW CHOPS GROW. 

(one to one and one-half parts potash to 1000 parts of -water), and the 
liquid, after standing some days at rest, may be poured off from any 
residue of starch. On adding acetic acid in slight excess, the purified 
albuminoids are separated in the solid state. By extracting succes- 
sively with weak, with strong, and with absolute alcohol, a form of 
casein (gluten-casein of Ritthausen) remains undissolved, which is perhaps 
identical with the casein (legumin) of the pea. 

On evaporating the alcoholic solution to one-half, there separates, on 
cooling, a brownish-yellow mass. This, when treated with absolute al- 
cohol, leaves vegetable-fibrin nearly pure. 

. Vegetable-fibrin is readily soluble in hot alcohol, but 
slightly so in cold alcohol. It does not at all dissolve in 
water. It has no fibrous structure like animal fibrin, but 
forms, when dry, a tough, horn-like mass. In composition 
it approaches animal-fibrin. 

Casein. — Animal casein is the peculiar ingredient of 
new cheese. It exists dissolved to the extent of 3 to 6 
per cent in fresh milk, unlike albumin is not coagulated 
by heat, but is coagulated by acids, by rennet, (the mem- 
brane of the calf's stomach), and by heating to boiling 
with salts of lime and magnesia. 

Exp. 50. — Observe the coagulation of casein when milk is treated 
with a few drops of sulphuric acid. Test the curd with nitrate of 
mercury. 

Exp. 51. — Boil milk with a little sulphate of magnesia (epsom salts) 
until it curdles. 

When casein is separated from milk by rennet, as in 
making cheese, it carries with it a considerable portion of 
the phosphates and other salts of the milk; these salts 
are not found in the casein precipitated by acids, being 
held in solution by the latter. 

The casein of milk coagulates spontaneously when it 
stands for some time. Casein has recently been detected 
in the brain of animals. (Hoppe-Seyler, Med. Chem. Uh- 
ters,^ II.) 

Vegetable casein,— rrl^hhs, substance is found in large pro- 
portion (17 to 19 per cent) in the pea and bean, and in- 
deed generally in the seeds of the so-called leguminous 
plants. It closely resembles milk-casein in all respects. 



THE VOLATILE PAET OF PLANTS. 101 

Exp. 53.— Prepare a solution of vegetable caseiu from crushed peas, 
oats, almonds, or pea-uuts, by soaking them for some hours in warm 
water, and allowing the liquid to settle clear. Coagulate the casein by- 
addition of an acid to the solution. It may be coagulated by rennet, 
and by salts of magnesia and lime, in the same manner as animal casein. 

The Chinese prepare a vegetable cheese hy boiling peas 
to a pap, straining the liquor, adding gypsum until coagu- 
lation occurs, and treating the curd thus obtained in the 
same manner as practiced with milk-cheese, viz.: salt- 
ing, pressing, and keeping until the odor and taste of 
cheese are developed. It is cheaply sold in the streets of 
Canton under the name of Tao-foo, Vegetable casein 
occurs in small quantity in oats, the potato, and many 
plants ; and may be exhibited by adding a few drops of 
acetic acid to turnip juice, for instance, which has been 
freed from albumin by boiling and filtering. The casein 
from peas and leguminous seeds has been designated 
legumin^ that of the oat has been named avenin. Almonds 
yield a casein, which has been termed emulsin. As al- 
ready mentioned, casein (Ritthausen's gluten-casein) exists 
in wheat-gluten, and in rye. Each of these sources yields 
a casein of somewhat peculiar characters ; the causes of 
these differences are not yet ascertained, but probably lie 
in impurities, or result from mixture of other albuminoids. 

In crude wheat-gluten two other albuminoids exist, viz. : 

Oliadin, or vegetable glue, is very soluble in water and 
alcohol. It strongly resembles animal glue. 

Mucedin resembles gliadin, but is less soluble in strong 
alcohol, and is insoluble in water. When moist, it is yel- 
lowish-white in color, has a silky luster, and slimy consist- 
ence. It exists also in rye grain. (Ritthausen, Jour, far 
FraJct, Chem., 88, 141 ; and 99, 463.) 

Composition of the Albuminoids. — There are various 
reasons why the exact composition of the bodies just de- 
scribed is a subject of uncertainty. They are, in the first 
place, naturally mixed and associated with other matters 



102 HOW CROPS GROW. 

from which it is very difficult to separate them fully. 
Again, if we succeed in removing foreign substances, it 
must usually be done by the aid of acids, alkalies, and 
other strong reagents, which easily alter or destroy their 
proper characters and composition. Finally, if we analyze 
the pure substances, our methods of analysis are perhaps 
scarcely delicate enough to indicate their differences with 
entire accuracy. 

The results of chemical investigation demonstrate that 
the albuminoids are either identical in composition or 
differ but slightly from each other, as is seen from the 
Table below. The deduction of a correct atomic formula 
from these analyses is perhaps impossible in the present 
state of our knowledge. 

In the subjoined Table are given analyses of the albuminoids 
which have been dcecribed. Tliose indicated by asterisks are recent re- 
sults of Dr. Ritthausen ; the others are average statements of the best 
analyses, (after Gorup-Besanez, Org. Chemie, p. 611.) 

COMPOSITION OF ALBUMINOIDS. 

Carbon. Hydrogen. Nitrogen. Oxygen. Sulphur. 

Animal albumin 53.5 7.0 15.5 23.4 1.6 

Vegetable albumiu.... 53.4 7.1 15.6 23.0 0.9 

Blood fibrin 53.6 7.0 17.4 21.8 1.3 

Flesh fibrin 54.1 7.3 16.0 21.5 1.1 

Wheat fibrin* 54.3 7.3 16.9 20.6 1.0 

Animal casein 53.6 7.1 15.7 22.6 1.0 

Vegetable casein 50.5 6.8 18.0 24.3 0.5 

Gluten-casein*"] 51.0 6.7 16.1 25.4 0.8 

Gliadiu* J.wheat53.6 7.0 18.1 31.5 0.8 

Mucedin* j 54.1 6.9 16.6 21.5 0.9 

Phosphorus is not included in the above table, for the reason that in 
all cases its quantity, and in most instances its very presence, is still un- 
certain. Voelcker and Norton found in vegetable casein 1.4 to 2.3 per 
cent of phosphorus, and smaller quantities have been mentioned by 
other of the older analysts as occurring in albumin and fibrin. The 
phosphorus of these and of animal casein is thought not to belong to 
the albuminoid, but to be due to au admixture of phosphate of lime. 

In his recent investigation of gluten-casein, Ritthausen found phos- 
phoric acid that appears to have been partially uucomblned with a fixed 
base, and to have therefore resulted from phosphorus in organic combi* 



THE VOLATILE PAET OF PLANTS. 103 

nation. It is not unlikely that vegetable casein may contain an admix- 
ture of protagon (p. 93), or tlie products of its decomposition, from 
which it is not easy to procure a separation. 

Mutual Relations of the Albuminoids. — Some have 
supposed that these bodies are identical in composition, 
the differences among the analytical results being due to 
foreign matters, and differ from each other in the same 
way that cellulose and starch differ, viz. : on account of 
different arrangement of the atoms. Others formerly 
adopted the notion of Mulder, to the effect that the albu- 
minoids are compounds of various proportions of hypothet- 
ical sulphur and phosphorus compounds, with a common 
ingredient, which he termed ^ro^e^?^, (from the Greek sig- 
nifying "to take the first place," because of the great 
physiological importance of such a body.) Hence the 
albuminoids are often called the protein-bodies. The trans- 
formations which these substances are capable of under- 
going, sufficiently show that they are closely related, with- 
out, however, satisfactorily indicating in what manner. 

In the animal organism, the albuminoids of the food, of 
whatever name, are dissolved in the gastric juice of the 
stomach, and pass into the blood, where they form blood- 
albumin and blood-fibrin. As the blood nourishes the 
muscles, they are modified into flesh-fibrin, or entering the 
lacteal system, are converted into casein, while in the ap- 
propriate part of the circulation they are formed into the 
albumin of the o^^g^ or embryo. 

In the living plant, similar changes of place and of char- 
acter occur among these substances. 

Finally, outside the organism the following transforma- 
tions have been observed : Flesh-fibrin exposed while 
moist to the air at a summer temperature for some days, 
dissolves into a liquid ; if this liquid be heated to near 
boiling, coagulation, takes place, and the substance which 
separates has the properties of albumin. On removing 
the albumin and adding vinegar to the remaining liquid, 



104 HOW CKOPS GEOW. 

a curdy coagulumis formed, wliicli agrees in its properties 
with casein. (Bopp, Aim. Ch. JPh., 60, -p. 30 ; Gunning, 
Joicr. fur Praht. Chem.^ 69, p. 52.) 

Lehmann has shown that when albumin is dissolved in 
potash, and mixed with a little milk-sugar and oily fat, the 
mixture coagulates with rennet exactly as milk curdle. 
(Gorup-Besanez, Phys. Chem., p. 139.) 

Sullivan has observed that the casein of milk which was 
kept in closed air-tight vessels for a long time, at first co- 
agulated, but afterward dissolved again to a nearly clear 
liquid, which was found to contain no casein, but by heat- 
ing, coagulated, showing the conversion of casein into 
albumin, or a similar body. {Fhil. Mag., 4, XYIII, 203.) 

Some maintain that casein is not a distinct albuminoid, 
but a compound of albumin with potash, containing, ac- 
cording to Lieberkuhn, 5.5°| „ of this alkali. Its peculiarities 
are in part due to its natural association with phosphate 
of potash. Kiihne, Phys. Ghem., 1868, p. 565. See, how- 
ever, Schwarzenbach, A7in. Ch. u. Ph.^ 144, p. 63. 

The Alhwninoids in Animal Nutrition. — ^We step 
aside for a moment from our proper plan to direct atten- 
tion to the beautiful adaptation of this group of organic 
substances to the nutrition of animals. Those bodies which 
we have just noticed as the animal albuminoids, together 
with others of similar composition, constitute a large share 
of the healthy animal organism, and especially characterize 
its actual working machinery, being essential ingredients 
of the muscles and cartilages, as well as of the nerves and 
brain. They likewise exist largely in the nutritive fluids 
of the animal — in blood and milk. So far as we know, the 
animal body has not the power to produce a particle of 
albumin, or fibrin, or casein ; it can only transform these 
bodies as presented to it from external sources. They are 
hence indispensable ingredients of food, and have been 
aptly designated by Liebig as the plastic eletnents of nu- 
trition. It is, in all cases, the plant which originally con- 



THE VOLATILE PAET OF PLANTS. 105 

structs these substances, and places them at the disposal 
of the animal. 

The albuminoids are mostly capable of existing in the 
liquid or soluble state, and thus admit of distribution 
throughout the entire animal body, as blood, etc. They 
likewise readily assume the solid condition, thus becoming 
more permanent parts of the living organism, as well as 
capable of indefinite preservation for food in the seeds and 
other edible parts of plants. 

Complexity of Constitution. — The albuminoids are high- 
ly complex in their chemical constitution. This fact is 
shown as well by the multiplicity of substances which may 
be produced from them by destructive and decomposing 
processes, as by the ease with which they are broken up 
into other and simpler compounds. Subjected in the solu- 
ble or moist state to the action of warm air, they speedily 
decompose or putrefy, yielding a large variety of products. 
Heated with acids, alkalies, and oxidizing agents, they all 
give origin to the same or to analogous products, among 
Avhicli no less than twenty difi*erent compounds have been 
distinguished. 

Occurrence in Plants — Aleurone. — It is only in the old 
and virtually dead parts of a living plant that albuminoids 
are ever wanting. In the young and growing organs they 
are abundant, and exist dissolved in the sap or juices. 
They are especially abundant in seeds, and here they are 
deposited in an organized form, chiefly in grains similar to 
those of starch, and are nearly or altogether insoluble in 
Avater. 

These grains of albuminoid matter are not, m many 
cases at l^ast, pure albuminoids. They appear to contain 
vegetable albumin, casein, fibrin, etc., associated together, 
though, in general, casein and fibrin are largely predomi- 
nant. Hartig, who first described them minutely, has dis- 
tinguished them by the name cileurone, a term which we 
may conveniently employ. By the word aleurone is not 



106 



HOW CEOPS GROW. 



meant simply an albuminoid, or mixture of albuminoids, 
but the organized granules found in the jolant, of which 
the albuminoids are chief ingredients. 

In Fig. 18 is represented a magnified slice through the 
outer cells, (bran,) of a husked oat kernel. The cavities 
of these outer cells, «, c, are chiefly occupied with very 





ooooa 




Tig-. 18. 



Fig. 19. 



fine grains of aleurone, (casein.) In one cell, J, are seen 
the much larger starch grains. In the interior of the oat 
kernel and other cereal seeds, the cells are chiefly occupied 
with starch, but throughout grains of aleurone are more 
or less intermingled. 

Fig. 19 exhibits a section of the exterior part of a flax- 
seed. The outer cells, «, contain vegetable mucilage ; the 
interior cells, e, are mostly filled with minute grains of 
aleurone, among which droplets of oil,/*, are distributed. 

In Fig. 20 are 
shown some of the 
forms assumed by in- 
dividual albuminoid- 
grains ; a is aleurone 
from the seed of the vetch, 
from flax-seed, d from the fruit of the bayberry, (Myrica 




h from the castor bean, c 



THE VOLATILE PART OF PLANTS. 



107 



cerifera^ and e from mace, (an appendage to the nutmeg, 
or fruit of the Myristica onoschata.) 

Crystalloid aleurone. — It has been already remarked 
that crystallized albuminoids may be obtained from the 
blood of animals. It is equally true that bodies of similar 
character exist in plants, as was first observed by Hartig, 
[EntwicJcelungsgeschichtc des PflanzenJceims^ p. 104.) In 
form they sometimes imitate crystals quite perfectly, Fig. 
21, a / in other cases, 5, they are rounded masses, having 
some crystalline planes or facets. They are soft, yield 
easily to pressure, swell up to double their bulk when 




Fig. 21. 

soaked in weak acids or alkalies, and their angles have 
none of the constancy peculiar to proper crystals. There- 
fore the term crystalloid^ i. e. having the likeness of crys- 
tals, is more appropriate than crystallized. 

As Cohn first noticed, {Jour, far JPraJct. Ghem.^ 80, 
p. 129,) crystalloid aleurone may be observed in the outer 
portions of the potato tuber, in which it invariably pre- 
sents a cubical form. It is best found by examining the 
cells that adhere to the rind of a potato that has been 
boiled. In Fig. 21, a represents a cell from a boiled pota- 
to, in the centre of which is seen the cube of aleurone. 
It is surrounded by the exfoliated remnants of starch- 
grains. In the same figure, h exhibits the contents of 
a cell from the seed of the bur reed, {Sparganmm ramo- 
sum,) a plant that is common along the borders of ponds. 
In the center is a comparatively large mass of aleurone, 
having crystalloid facets. 



108 now CKOPS GROW. 

According to Maschke, {Jour, fur Br. Ch.^ 79, p. 148,) 
the crystalloid aleurone that is abundant in the Brazil 
nut, is a compound of casein v:ith some acid of imJcnoimi 
composition. This aleurone may be dissolved in water, 
and recovered in its original form on evaporation. 

Kubel's analysis of aleurone, prepared from the Brazil 
nut by Hartig, gave its content of nitrogen 9.46 />e?' cent. 
Aleurone from the yellow lupin yielded him 9.2Qper cent. 
Since pure casein has 16 to 18 per cent of nitrogen, the 
aleurone contained about 52 to 59^6/' cent of albuminoids. 

Estimation of the Albuminoids. — The quantitative sei> 
aration of these bodies is a matter of great difficulty and 
uncertainty. For most purposes their collective quantity 
in any organic substance may be calculated with sufficient 
accuracy from its content of nitrogen. All the albumin- 
oids contain, on the average, about \^per cent of nitrogen. 
This divided into 100 gives a quotient of 6.25. If, now, 
the percentage of nitrogen that exists in a given plant be 
multiplied by 6.25, the product will represent its percent- 
age of albuminoids, it being assumed that all the nitrogen 
of the plant exists in this form, which in most cases is prac- 
tically true. 

Frtihling and Grouven have recently investigated the 
condition of the nitrogen of various plants, and have found 
that nitric acid, (N^ O^,) which in the form of nitrate of 
potash has long been known to occur in vegetation, is 
present in but trifling quantity in most agricultural plants. 
In mature clover, esparsette, lucern, wheat, rye, oats, bar- 
ley, the pea, and the lentil, it did not exceed 2 parts in 
10,000 of the air-dry plant. In maize, they found twice 
this quantity ; in beet and potato tops alone of all the plants 
examined was nitric acid present to the amount of four- 
tenths of one per cent, ( Ys. St., IX, 153.) Salts of am- 
monia (N II3) likewise often exist in plants, but as a rule 
in quite inconsiderable quantities. 



I 



THE VOLATILE PART OF PLANTS. 109 

AYERAGE QUANTITY OF ALBUMINOIDS IN YAUIOUS YEQETABLB PRODUCTS. 

per cent. 

Maize fodder, green 1,2 

Beet tops " 1.9 

Carrot tops " 3.5 

Meadow grass " 3.1 

Red clover " 3.7 

" White clover " 4.0 

Turnips, fresh 1.0 

Carrots " 1.3 

Potatoes " 2.0 

Corn cobs, air-dry 1.4 

Straw of summer grain, air-dry 2.6 

Straw of winter " " 3.0 

Pea straw *' 7.3 

Bean straw " 10.2 

Meadow hay •' 8.5 

Red clover hay •' 13.4 

White clover hay " 14.9 

Buckwheat kernel " 7.8 

Barley " " 10.0 

Maize " " 10.7 

Rye " " 11.0 

Oat " " 12.0 

Wheat " " 13.2 

Pea " " 22.4 

Bean " " 24.1 

Lupine " ' '• 34.5 



APPENDIX TO § 4. 
Chlorophyll : Tannin : Alkaloids. 

Before dismissing the subject of the Proximate Elements of plants, we 
must notice several other substances of subordinate agricultural .inter- 
est. Two of these, viz., Chlorophyll and Tannin^ though not figuring in 
the analysis of agricultural plants, are nevertheless of almost universal 
occurrence in all forms of vegetation, though usually in very minute 
quantity. 

Cliloropliyll, i. e. leaf-green, is the name applied to the substance 
which occasions the green color in vegetation. It is found in all the sur- 
foce of annual plants and of the annually renewed parts of perennial 
plants. It might readily he supposed that it constitutes a large portion 
of the leaves of vegetation, but the ftxct is quite otherwise. The greeu 



110 now CROPS GROW. 

parts of plants usually contain chlorophj-ll only at tlieir surface, and 
in quantity no greater than colored fabrics contain the particles of dye. 

Chlorophyll being soluble in ether, accompanies fat or wax when these 
are removed from green vegetable matters by this solvent. It is soluble 
in chlorhydric and sulphuric acids, imparting to these liquids its in- 
tense green color. According to Pfaundler, the (impure ?) chlorophyll 
of grass has the following percentage composition : 
Carbon 60.85 
Hydrogen 6.39 
Oxygen 32.78 " 

Fremy has shown that chlorophyll may be easily decomposed into two 
coloring matters, a yellow, Zani?iop7iyU, and a blue, Cyano2yhyll. This is 
accomplished by treating chlorophyll with a mixture of chlorhydric acid 
and ether ; the cyanophyll dissolves in the latter, and the zanthophyll is 
taken up by the former solvent. The yellow color of autumn leaves is 
perhaps due to zanthophyll. 

According to Sachs, there exists in those parts of plants, which, though 
not green, are capable of becoming so, a colorless substance, Leucophyll, 
which, in contact with oxygen, acquires a green color, being converted 
into chlorophyll. 

Xannin is the general designation of the bitter, astringent prin- 
ciples, (used in leather-making,) of the bark and leaves of the hemlock, 
oak, sumach, plum, pear, and many other trees, of tea, coflfee, and of 
gall-nuts. It is found in small quantity in the young bean plajit, and in 
many germinating seeds. 

Tannin is closely related to the carbohydrates, as is .demonstrated 
alike by the microscopic study of its development in the plant, and by 
our knowledge of its chemical composition. The tannins are weak 
acids, and are distinguished, according to their origin, as Oallotannic 
acid (from nut-galls), Caffeotannic acid (from coffee), Qiiercitannic acid 
(from the oak), etc. As already hinted, the tannins are Ghicosidcs, or 
compounds of sugar, with some other substance. In gall-tannin the 
sugar is glucose, and the substance associated "with, or rather yielded by 
it on decomposition, is known as Gallic acid. By boiling gall-tannin 
with a dilute acid, or by subjecting its solution to fermentation, decom- 
position into the two substances named is accomplished. 

According to Strecker, the composition of gall-tannin and this con- 
version are indicated by the following formulae : 

Ta7i7iiii. Water. Gallic acid. Glucose. 

2 (C27 H22 On) -1- 8 (H2 0) = 6 (Ct He O5) + C12 H24 O12 

The Alkaloids are a class of bodies very numerous in poisonous and 
medicinal plants, of which they usually constitute the active principle. 
Those which have an agricultural interest are Mcotiii, Caffein, and 
Theobromin. 

rVicotin, Cio Hh N2, is the narcotic and extremely poisonous prin- 
ciple in tobacco, where it exists in combination with malic and citric 



THE ASH OF PLANTS. Ill 

acids. In the pure state it is a colorless, oily liquid, having the odor 
of tobacco in an extreme degree. It is inflammable and volatile, and so 
deadly that a single drop will kill a large dog, French tobacco contains 
7 or 8 p. c; Virginia, 6 or 7 p. c; and Maryland and Havanna, about 2 p. 
e. of nicotin. Nicotin contains 17.3 p. c. of nitrogen, but no oxygen. 

Ca^fiein, Cs Hio N4 O2, exists IncoflFeeand tea combined with tannic 
acid. In the pure state it forms white, silky, fibrous crystals, and has a 
bitter taste. In coffee it is found to the extent of one-half per cent ; in 
tea it occurs in much larger quantity, sometimes as high as 6 per cent. 

'I'lieo'bromin, C7 B.» N4 O2, resembles caffein in its characters, 
and is closely related to it in chemical composition. It is found in the 
cacao-bean, from which chocolate is manufactured. 

The alkaloids are remarkable from containing nitrogen, and from hav- 
ing strongly basic characters. They derive their designation, alkaloids, 
from their likeness to the alkalies. 



CHAPTER II. 
THE ASH OF PLANTS. 

§1. 
THE INGREDIENTS OF THE ASH. 

As has been stated, the volatile or destructible part of 
plants, *.«. the part which is converted into gases or vapors 
under the ordinary conditions of burning, consists chiefly 
of Carbon, Hydrogen, Oxygen, and Nitrogen, together 
with minute quantities of Sulphur and Phosphorus. 
These elements, and such of their compounds as are of 
general occurrence in agricultural plants, viz., the Organic 
Proximate Principles, have been already described in detail. 

The non-volatile part or ash of plants also contains, or 
may contain. Carbon, Oxygen, Sulphur, and Phosphorus.. 
It is, however, in general, chiefly made up of eight other 
elements, whose common compounds are fixed at the ordi- 
nary heat of burning. 



112 now CEOPS GROW. 

In the subjoined table, the names of the 12 elements of 
the ash of plants are given, and they are grouped under 
two heads, the non-metals and the metals^ by reason of an 
important distinction in their chemical nature. 

ELEMENTS OF THE ASH OF PLANTS. 

Non-Mctals. Metals. 

Oxyj^en Potassium 

Carbon Sodium 

Sulplmr Calcium 

Phosphorus Magnesium 

Silicon Iron 

Chlorine Manganese 

If to the above be added 

Hydrogen and Nitrogen 
the list includes all the elementary substances that belong 
to agricultural vegetation. 

Hydrogen is never an ingredient of the perfectly burned 
O/Ud dry ash of any plant. 

Nitrogen may remain in the ash under certain conditions 
in the form of a Cyanide., (compound of Carbon and Ni- 
trogen,) as will be noticed hereafter. 

Besides the above, certain other elements are found, cither occasion- 
ally in common plants, or in some particular kind of vegetation : these 
are Iodine, Bromine, Fluorine, Titanium, Arsenic, Lithium, Rubidium, 
Barium, Aluminum, Zinc, Copper. 

We may now complete our study of the Composition 
of the Plant by attending to a description of those ele- 
ments that are peculiar to the ash, and of those compounds 
which may occur in it. 

It will be convenient also to describe in this section 
some substances, which, although not ingredients of the 
ash, may exist in the plant, or are otherwise important to 
be considered. 

. The non-metallic elements, which we shall first no- 
tice, though differing more or less widely among them- 
selves, have one point of resemblance, viz., they and their 
compounds with each other have acid properties, i. e. they 



THE ASII OF PLANTS. 113 

either arc acids in the ordinary sense of being sour to the 
taste, or enact the part of acids by uniting to metals or 
metallic oxides, to form salts. We may, therefore, desig- 
nate them as the acid elements. They are Oxygen, Sulphur, 
Phosphorus, Carbon, Silicon, and Chlorine. (Less com- 
mon are Arsenic, Titanium, Iodine, Bromine, and Fluorine.) 

With the exception of Silicon, (and Titanium,) and the 
denser forms of Carbon, these elements by themselves are 
readily volatile. Their compounds with each other, which 
may occur in vegetation, are also volatile, with two ex- 
ceptions, viz.. Silicic and Phosphoric acids. 

In order that they may resist the high temperature at 
which ashes are formed, they must be combined with the 
metallic elements or their oxides as salts. 

Oxygen, Symbol O, atomic weight IG, is an ingredient 
of the ash, since it unites with nearly all the other elements 
of vegetation, either during the life of the plant, or in the 
act of combustion. It unites with Carbon, Sulphur, Phos- 
phorus, and Silicon, forming acid bodies ; while with the 
metals it produces oxides, which have the characters of 
bases. Chlorine alone of the elements of the plant does 
not unite with oxygen, either in the living plant, or during 
its combustion. 

CAKBON AND ITS COMPOUNDS. 

Carboil) 8ym. C, at. wt. 12, has been noticed already 
with sufficient fulness, (p. 31.) It is often contained as 
charcoal in the ashes of the plant, owing to its being en- 
veloped in a coating of fused saline matters, which shield 
it from the action of oxygen. 

Carbonic acid, Sym. C O^, m,olecular weight, 44, is the 
colorless gas which causes the sparkling or effervescence 
of beer and soda water, and the frothing of yeast. 

It is formed by the oxidation of carbon, when vegetable 
matter is burned, (Exp. 6.) It is, therefore, found in the 
ash of plants, combined with those bases which in the liv- 



114 HOW CROPS GROW. 

ing organism existed in union with organic acids ; the lat- 
ter being destroyed by burning. 

It also occurs in combination with lime in the tissues of 
many plants. Its compounds with bases are carbonates^ 
to be noticed presently. When a carbonate, as marble or 
limestone, is drenched with a strong acid, like vinegar or 
muriatic acid, the carbonic acid is set free with effer- 
vescence. 

Cyanog'eii, Sum. CN.— This important compound of Carbon and 

Nitrogen is a gas which has an odor resembling that of peach-pits, 

and Avhicli burns on contact witlr a liglited taper with a fine purple flame. 

• In its union with oxygen by combustion, carbonic acid is formed, and 

nitrogen set free, 

Cyanogen may be prepared by heating an intimate mixture of two parts 
by weight of ferrocyanide of potassium, (yellow prussiate of potash,) and 
three parts of corrosive sublimate. The operation may be conducted in 
a test tube or small flask, to the mouth of which is fitted a cork pene- 
trated by a narrow glass tube. On applying heat, the gas issues, and 
may be set on fire to observe its beautiful flame. 

Cyanogen, combined with iron, forms the Prussian blue of commei'ce, 
and its name, signifying the blue-producer, was given to it from that cir- 
cumstance. 

Cyanogen unites with the metallic elements, giving rise to a series of 
bodies which are termed Cyanides. Some of these often occur in small 
quantity in the ashes of plants, being produced in the act of burning by 
the union of nitrogen with carbon and a metal. For this result, the 
temperature must be very high, carbon must be in excess, the metal 
is usually potassium or calcium, the nitrogen may be either free nitrogen 
of the atmosphere or that originally existing in the organic matter. 

With hydrogen, cyanogen forms the deadly poison hydrocyanic or prus- 
sic acid, H Cy, which is produced from aniygdaline, one of the ingre- 
dients of bitter almonds, peach, and cherry seeds, when these are crush- 
ed in contact with water. 

When a cyanide is brought in contact with steam at high temperatures, 
it is decomposed, all its nitrogen being converted into ammonia. 

Cyanogen is a normal ingredient of one common plant. The oil of 
mustard is the suJpho-cyanide ofallyle, C3 II5 CNS. 

SULPHUR AND ITS COMPOUNDS. 

Sulphur, 8ym. S, at. wt. 32. — The properties of this 
element have been already described, (p. 42.) Some of 



THE ASH OF PLANTS. 115 

its compounds have also been briefly alluded to, but re- 
quire more detailed notice. 

Siilphydric Acid, Sym H2 S, mo. wt. 34. This substance, fa- 
miliarly known as sulpliuretted hydrogen, occurs dissolved in the water 
of numerous so-called sulphur springs, as those of Avon and Sharon, N. 
Y., from which it escapes as a fetid gas. It is not unfrequently emitted 
from volcanoes and fumaroles. It is likewise produced in the decay of 
organic bodies which contain sulphur, especially eggs, the intolerable 
odor of which, when rotten, is largely due to this gas. It is evolved 
from manure heaps, from salt marshes, and even from the soil of moist 
meadows. 

The ashes of plants sometimes yield this gas when they are moisten- 
ed with water. In such cases, a sulphide of potassium or calcium has been 
formed in small quantity during the incineration. 

Sulphydric acid is set free in the gaseous form by the action of an acid 
on various sulphides, as those of iron, (Exp. 17,) antimony, etc., as well as 
by the action of water on the sulphides of the alkali and alkali-earth metals. 
It may be also generated by passing hydrogen gas into melted sulphur. 

Sulphuretted hydrogen has a slight acid taste. It is highly poisonous 
and destructive, both to animals and plants. 

Sulpliiiiroiis Acid, Sym. SO2, mo. wt. 64. When sulphur is 
burned in the air, or in oxygen gas, it forms copious white suffocating 
fumes, which consist of one atom of sulphur, united to two atoms of 
oxygen; S O2, (Exp. 15.) 

Sulphurous acid is characterized by its power of discharging, for a time 
at least, most of the red and blue vegetable colors. It has, however, no 
action oh many yellow colors. Straw and wool are bleached by it in the 
arts. 

Sulphurous acid is emitted from volcanoes, and from fissures in the 
soil of volcanic regions. It is produced when bodies containing sulphur 
are burned with imperfect access of air, and is thrown into the atmos- 
phere in large quantities from fires which are fed by mineral coal, as well 
as from the numerous roasting heaps of certain metallic ores, (sulphides,) 
which are wrought in mining regions. 

Sulphurous acid may unite with bases, yielding salts known as sul- 
phites, some of which, viz., sulphite of lime and sulphite of soda, are em- 
ployed to check or prevent fermentation, an effect also produced by the 
acid itself. 

Anhydrous* Sulphuric Acid, JS^m. SO3, mo. wt. 80; is 
known to the chemist as a white, silky solid, which attracts 
moisture with great avidity, and, when thrown into water, 
hisses like a hot iron, forming the hydrated sulphuric acid. 



* i. e., free from water. 



116 HOW CROPS GEOW. 

Hydrated Sulphuric Acid, Sym. H, O SO3 or H, SO,, 

mo. wt. 98 — the sulphuric acid of commerce — is a substance 
of the highest importance, its manufacture being the basis 
of the chemical arts. In its concentrated form it is known 
as oil of vitriol^ and is a colorless, heavy liquid, of an 
oily consistency, and sharp, sour taste. 

It is manufactured on the large scale by mingling sul- 
phurous acid gas, nitric acid gas, and steam, in large lead- 
lined chambers, the floors of which are covered with wa- 
ter. The sulphurous acid takes up oxygen from the nitric 
acid, and the sulphuric acid thus formed dissolves in the 
water, and is afterwards boiled down to the proper strength 
in glass vessels. 

The chief agricultural application of commercial sul- 
phuric acid is in the preparation of " superphosj)hate of 
lime," which is consumed as a fertilizer in immense quan- 
tities. This is made by mixing together dilute sulphuric 
acid with bone-dust, bone-ash, or some mineral phosphate. 

Sulphuric acid occurs in the free state, though extreme- 
ly dilute, in certain natural waters, as in the Oak Orchard 
Acid Spring of Orleans, IST. Y., where it is produced by 
the oxidation of sulphide of iron. 

Sulphuric acid is very corrosive and destructive to most 
vegetable and animal matters. 

Exp. 53. — Stir a little oil of vitriol Avith a pine stick. The wood is 
immediately browned or blackened, and a portion of it dissolves in tlie 
acid, commuuicatiuj^ a dark color to the latter. Tlie commercial acid is 
often brown from contact with straws and chips. 

Strong sulphuric acid produces great heat when mixed with water, as 
is done for making superphosphate. 

Exp. 54. — ^Place in a thin glass vessel, as a beaker glass, 30 c. e. of wa- 
ter; into this pour in a fine stream 130 grams of oil of vitriol, stirring 
all the while with a narrow test tube, containing a teaspoonful of water. 
If the acid be of full strength, so much heat is thus generated as to boil 
the water in the stirring tube. 

In mixing oil of vitriol and water, the acid should always be slowly 
poured into the water, with stirring, as above directed. When water is 
added to the acid, it floats upon the latter, or mixes with it but super- 



THE ASH OF PLANTS. 117 

flcially, and the liquids may be thrown about by the sudden formation 
of steam at the points of contact, when subsequently stirred. 

Sulphuric acid forms with the bases an important class 
of salts — the sulphates — to be presently noticed, some of 
which exist in the ash, as well as in the sap of plants. 
When organic matters containing sulphur, as hair, album- 
in, etc., are burned with full access of air, tliis element re- 
mains in the ash as sulphates, or is partially dissipated as 
sulphurous acid. 

PHOSPHOEUS AND ITS COMPOUNDS. 

Phosphorus, Sym. P, at. wt. 31, has been sufficiently 
described, (p. 43.) Of its numerous compounds but two 
require additional notice. 

Anhydrous Phosphoric Acid, Sym. P„ O^,, mo. wt. 142, 
does not occur as such in nature. When phosphorus is 
burned in dry air or oxygen, anhydrous phosphoric acid 
is the snow-like product, (Exp. 18.) It has no sensible 
acid properties until it has united to water, which it com- 
bines with so energetically as to produce a hissing noise 
from the heat developed. On boiling it with water for 
some time, it completely dissolves, and the solution con- 
tains — 

Ilydratcd Phosphoric Acid, Sym. P, 0„ 3 ri„ O, 196, 
or H3 PO4, 98. — The chief interest which this compound 
has for the agriculturist lies in the fact that the com- 
binations which are formed between it and various bases 
— phosphates — arc among the most important ingredients 
of plants and their ashes. 

When bodies containing phosphorus in other forms than 
phosphoric acid, as protagon, (p. 93,) and, perhaps, some 
of the albuminoids, are disorganized by heat or decay, the 
phosphorus appears in the ashes or residue, in the con- 
dition of phosphoric acid or phosphates. 

The formation of several phosphates has been shown in 



118 HOW CROPS GEOW. 

Exp. 20. Further account of them will be given under 
the metals. 

CHLOEINE AND ITS COMPOmiTDS. 

ChlotinC) 8ym. CI, at. wt. 35.5. — This element exists in 
the free state as a greenish-yellow, suffocating gas, which 
has a peculiar odor, and the property of bleaching vege- 
table colors. It is endowed with the most vigorous 
affinities for many other elements, and hence is never met 
with, naturally, in the free state. 

Sprengel claims to have found that Olaux maritima and Salicornia her- 
bacea, plants growing in salt marshes, exhale chlorine. He says that the 
clilorine thus evolved is very quickly converted into chlorliydric acid, 
by acting ou the vapor of water which exists in the atmosphere. Such 
an exhalation of chlorine is manifestly impossible. The gas, were it 
eliminated within the plant, would be consumed before it could escape 
into the atmosphere. Chlorhydric acid is evolved from the mud of salt 
marshes when left bare by ebb of the tide, and exposed to the heat of 
the summer sun. It comes from the mutual decomposition of chloride 
of magnesium and water, 

Mg CI2 + Ha O = Mg O + 2 H CI. 

Exp. 55. — Chlorine may be prepared by heating a mixture of chlor- 
hydric acid and black oxide of manganese or red-lead. The gas being 
nearly five times as heavy as common air, may be collected in glass bot- 
tles by passing the tube which delivers it to the bottom of the receiving 
vessel. -Care must be taken not to inhale it, as it energetically attacks 
the interior of the breathing passages, producing the disagreeable 
symptoms of a cold. 

Chlorine dissolves in water, forming a yellow solution. 
Yery weak chlorine water was found by Humboldt to fa- 
cilitate the sprouting of seeds. 

In some form of combination chlorine is distributed over 
the whole earth, and is never absent from the plant. 

The compounds of chlorine are termed chlorides, and 
may be prepared, in most cases, by simply putting their 
elements in contact, at ordinary or slightly elevated tem- 
peratures. 

Clilorliydric acid, also SydrocMoric acid, Sym. H CI, mo. wt. 
36.5. — When Chlorine and Hydrogen gases are mingled together, they 
slowly combine if exposed to diffused light; but if placed in the sun- 
shine, they unite explosively, and chloride of hydrogen or chlorhydric 



THE ASH OF PLAOTTS. 119 

acid is formed. This compound is a gas that dissolves with great avidity 
in water, forming a liquid which has a sharp, sour taste, and possesses 
all the characters of an acid. 

The muriatic acid of the apothecary is water holding in solution several 
hundred times its bulk of chlorhydric acid gas, and is prepared from com- 
mon salt, whence its ancient name spirits of salt. 

Chlorhydric acid is the usual source of chlorine gas. The latter is 
evolved from a heated mixture of this acid with peroxide of manganese. 
In this reaction the hydrogen of the chlorhydric acid imites with the 
oxygen of the peroxide of manganese, producing water, while chloride 
of manganese and free chlorine are separated. 

4 H CI + Mn O2 = Mn CI2 + 2 Ha O + 2 CI. 

When chlorine dissolved in water, is exposed to the sun-light, there 
ensues a change the reverse of that just noticed. Water is decomposed, 
its oxygen is set free, and chlorhydric acid is formed, 
H2 O + 2 CI = 2 H CI + O. 

This reaction probably takes place when the germination of seeds is 
hastened by chlorine. The oxygen thus liberated is doubtless the real 
agent which excites growth in the sleeping germ. 

The two reactions just noticed are instructive examples of the differ- 
ent play of affinities between several elements under unlike circum- 
stances. 

Chlorhydric acid, being volatile, does not occur in the ashes of plants, 
nor probably in the plant itself, unless, as may possibly happen, it is 
formed in, and exhales from the vegetation, as it sometimes does from 
the mud of salt marshes, (p. 118.) Chlorhydric gas is found in volcanic 
emanations. 

This acid is a ready means of converting various metals or metallic 
oxides into chlorides, and its solution in water is a valuable solvent and 
reagent for the purposes of the chemist. 

Iodine, Sym. I, at. tvt. 127.— This interesting body is a black solid at 
ordinary temperatures, having an odor resembling that of chlorine. Gent- 
ly heated, it is converted into a violet vapor. It occurs in sea-weeds, 
and is obtained from their ashes. It gives with starch a blue or purple 
compound, and is hence employed as a test for that substance, (p. 64.) 
It is analogous to chlorine in its chemical relations. It is not known to 
occur in sensible quantity in agricultural plants, although it may well 
exist in the grasses of salt-bogs, and in the produce of soils which are 
manured with sea-weed. 

Bromine and Fluorine may also exist in very small quantity in 
plants, but these elements require no further notice in this treatise. 

SILICOIT AND ITS COMPOUNDS. 

Silicon; Si/m. Si, at. wt 28. — This element, in the free 
state, is only known to the chemist. It may be prepared 



120 HOW CEOPS GEOW. 

in three modifications : one, a brown, powdery substance ; 
another, resembling black-lead, (p. 31,) and a third, that 
occurs in crystals, having the form and nearly the hard- 
ness of the diamond. 

Anhydrous Silicic Acid, Sym. Si O^, mo. tot. 60. — This 
compound, known also as Silica^ and anciently termed 
jSilex^ is widely diffused in nature, and occurs to an enor- 
mous extent in rocks and soils, both in tlie free state and 
in combination with other bodies. 

iFree silica exists in nearly all soils, and in many rocks, 
especially in sandstones and granites, in the form known 
to mineralogists as quartz. The glassy, white or trans- 
parent, often yellowish or red fragments of common sand, 
which are hard enough to scratch glass, are almost inva- 
riably this mineral. In the purest state, it is rocJc-crystal. 
Jasper, flint, and agate, are somewhat less pure silica. 

Silicates. — Anhydrous silicic acid is extremely insoluble 
in pure water and in most acids. It has, therefore, none 
of the sensible qualities of acids, but is nevertheless ca- 
pable of union with bases. It is slowly dissolved by strong, 
and especially by hot solutions of potash and soda, form- 
ing soluble silicates of these alkalies. 

Exp. 5G. — Formation of silicate of potash. Heat a piece of quartz or 
flint, as large as a clicstnut, as hot as possible in the lire, and quench 
suddenly in cold water. Reduce it to fine powder in a porcelain mortar, 
and boil it in a porcelain dish with twice its weight of caustic potash, 
and eight or ten times as much water, for two hours, taking care to sup- 
ply the water as it evaporates. Pour off the whole into a tall narrow 
bottle, and leave at rest until the undissolved silica has settled. The 
clear liquid is a basic silicate of potash, i. e. a silicate which contains a 
number of molecules of base for each molecule of silica. It has, in fact, 
the taste and feel of potash solution. The so-called water-glass^ now cm- 
ployed in the arts, is a similar silicate of potash or soda. 

When silica is strongly heated with potash or soda. Or 
with lime, magnesia, or oxide of iron, it readily melts to- 
gether and unites with these bodies, though nearly infus- 
ible by itself, and silicates are the result. The silicates 
thus formed with potash and soda are soluble in water, like 



THE ASH OP PLANTS. 121 

the product of Exp. 56, when the alkali exceeds a certain 
proportion — when highly basic ; but with silica in excess, 
(acid silicates,) they dissolve with difficulty. A mixed 
silicate of alkali and lime, alumina, or iron, with a large 
proportion of silica, is nearly or altogether insoluble, not 
only in v/ater, but in most acids — constitutes, in fact, ordi- 
nary glass. 

A multitude of silicates exist in nature as rocks and 
minerals. Ordinary clay, common slate, soapstone, mica, 
or mineral isinglass, feldspar, hornblende, garnet, and 
other compounds of frequent and abundant occurrence, are 
silicates. The natural silicates are of two classes, viz., the 
acid silicates, (containing a preponderance of siUca,) and 
basic silicates, (with large proportion of base): the former 
are but slowly dissolved or decomposed by acids, while 
the latter are readily attacked even by carbonic acid. 
Many native silicates are anhydrous, or destitute of water ; 
others are hydrous, i. e, they contain water as a large and 
essential ingredient. 

Hydrated Silica. — Various compounds of silica with 
water are known to the chemist. Of these but three need 
be mentioned here. 

Soluble Silica. — This body, doubtless a hydrate, is known 
only in a state of solution. It is formed when the solution 
of an alkali-silicate is decomposed by means of a large ex- 
cess of some strong acid, like the chlorhydric or sulphuric. 

Exp. 57. — Dilute half the solution of silicate of potash obtained in 
Exp. 56 with ten times its volume of water, and add diluted chlorhydric 
acid gradually until the liquid tastes sour. In this Exp. the chlorhydric 
acid decomposes and destroys the silicate of potash, uniting itself with 
the base with production of chloride of potassium, which dissolves in 
the water present. The silica thus liberated unites chemically with wa- 
ter, and remains also in solution. 

By appropriate methods Doveri and Graham have re- 
moved from solutions like that of the last Exp. everything 
but the silica, and obtained solutions of silica in pure wa- 
ter. Graham prepared a liquid that gave, when evaporat- 
6 



122 HOW CEOPS GEOW. 

ed and heated, 14 per cent of anhydrous silica. This so- 
lution was clear, colorless, and not viscid. It reddened 
litmus paper like an acid. Though not sour to the taste, 
it produced a peculiar feeling on the tongue. Evaporated 
to dryness at a low temperature, it left a transparent, 
glassy mass, which had the composition Si O^, H^O. This 
dry residue was insoluble in water. These solutions of silica ' 
in pure water are incapable of existing for a long time 
without suffering a remarkable change. Even when pro- 
tected from all external agencies, they sooner or later, usu- 
ally in a few days or weeks, lose their fluidity and trans- 
parency, and coagulate to a stiff jelly, from the separation 
of a nearly insoluble hydrate of silica, which we shall des- 
ignate as gelatinous silica. 

The addition of yoioo of an alkali or earthy carbonate, 
or of a few bubbles of carbonic acid gas to the strong so- 
lutions, occasions their immediate gelatinization. A mi- 
nute quantity of potash or soda, or excess of chlorhydric 
acid, prevents their coagulation. 

Gelatinous Silica. — This substance, which results from 
the coagulation of the soluble silica just described, usually 
appears also when the strong solution of a silicate has 
strong chlorhydric acid added to it, or when a silicate is 
decomposed by direct treatment w^ith a concentrated acid. 

It is a white, opaline, or transparent jelly, which, on dry- 
ing in the air, becomes a fine, w^hite powder, or forms 
transparent grains. This powder, if dried at ordinary 
temperatures, is 3 Si O.^, 2 H^O. At the temperature of 
212° F., it loses half its water. At a red heat it becomes 
anhydrous. 

Gelatinous silica is distinctly, though very slightly, sol- 
uble in water. Fuchs and Bresser have found by experi- 
ment that 100,000 parts of water dissolve 13 to 14 parts 
of gelatinous silica. 

The hydrates of silica which have been subjected to a 



THE ASH OF PLAN^TS. 123 

heat of 212° or more, appear to be totally insoluble in pure 
water. 

All the hydrates of silica are readily soluble in solutions 
of the alkalies and alkali carbonates, and readily unite 
with moist, slaked lime, forming silicates. 

Exp. 58. — Oelatinous Silica. — Pour a small portion of the solution of 
silicate of potash of Exp. 56, into strong chlorhydric acid. Gelatinous 
silica separates and falls to the bottom, or the whole liquid becomes a 
transparent jelly. 

Exp. 59. — Conversion of soluble into insoluble hydrated silica. — Evaporate 
the solution of silica of Exp. 57, which contains free chlorhydric acid, 
in a porcelain dish. As it becomes concentrated, it is very likely to ge- 
latinize, as happened in Exp. 58, on account of tlie removal of the sol- 
vent. Evaporate to perfect dryness, finally on a water-bath (i. e. on a 
vessel of boiling water which is covered by the dish containing the solu- 
tion). Add to the residue water, which dissolves away the chloride of 
potassium, and leaves insoluble hydrated silica, 3 Si O2, H2O, as a gritty 
powder. 

In the ash of plants, silica is usually found in combination 
with alkalies or lime, owing to the high temperature to 
which it has been subjected. 

In the plant, however, it exists chiefly, if not entirely, 
in the free state. 

Xitaniiim, an element which has many analogies with silicon, 
though rarely occurring in large, quantities, is yet often present in the 
form of Titanic acid, Ti O2, in rocks and soils, and according to Salm 
Horstmar may exist in the ashes of harley and oats. 

Arsenic, in minute quantity, has been found by Davy in turnips 
which had been manured with a fertilizer (superphosphate), in whose 
preparation, oil of vitriol, containing this substance, was employed. 

The metallic elements which remain to be noticed, viz. : 
Potassium, Sodium, Calcium, Magnesium, Iron, Manga- 
nese, (Lithium, Rubidium, Caesium, Aluminum, Zinc, 
and Copper,) are basic in their character, i. e., they unite 
with the acid bodies that have just been described to 
produce salts. Each one is, in this sense, the base of a 
series of saline compounds. 

Alkali-Metals. — The elements Potassium, Sodium, 
(Lithium, Rubidium, and Caesium), are termed alkali- 



124 HOW CROPS GROW. 

metals. Their oxides are very soluble in water, and are 
called alkalies. The metals themselves do not occur in 
nature, and can only be prepared by tedious chemical 
processes. They are silvery-white bodies, and are lighter 
than water. Exposed to the air, they quickly tarnish from 
the absorption of oxygen, and are rapidly converted into 
the corresponding alkalies. Thrown upon water, they 
mostly inflame and burn with great violence, decomposing 
the liquid, Exp. 11. 

Of the alkali-metals. Potassium is invariably found in 
all plants. Sodium is especially abundant in marine and 
strand vegetation ; it is generally found in agricultural 
plants, but is occasionally absent from them. 

POTASSIUM AND ITS COMPOUNDS. 

Potassium) sym. K f at. wt. 39. — When heated in the 
air, this metal burns with a beautiful violet light, and 
forms potash. 

Potash, Kfi, 94, is the alkali, and base of the potash- 
salts. 

Hydrate of Potash, K,0, Hp, 112, or K H 0,56, is the 
caustic potash of the apothecary and chemist. It may be 
procured in white, opaque masses or sticks, which rapidly 
absorb moisture and carbonic acid from the air, and 
readily dissolve in water, forming potash-lye. It strongly 
corrodes many vegetable and most animal matters, and 
dissolves fats, forming potash-soaps. It unites with acids 
like K3O, water being set free. 

SODIUM AND ITS COMPOUNDS. 

Sodium, Ka,t 23. — Burns with a brilliant, orange-yellow 
flame. 



* Prom the Latin name Kalium. 
t From the Latin name Natrium. 



THE ASH OF PLANTS. 125 

Soda, Na^O, 63. — This alkali, the base of the soda salts, 
is not distinguishable from potash by its sensible proper- 
ties. 

Hydrate of Soda, or Caustic Soda, Na,0, H^O, 80, or 
!N"a H O, 40. — This body is like caustic potash in appear- 
ance and general characters. It forms soaps with the 
various fats. While the potash-soaps are usually soft, 
those made with soda are commonly hard. 

LITHIUM : RUBIDIUM : CAESIUM. 

Ijithiuin, Li, 7. — The compounds of this metal are of much rarer 
occurrence than those of Potassium and Sodium. The element itself is 
the lif;htest metal known, being but little more than half as heavy as 
water. It burns with a vivid white light when heated in the air. 

Ijitltia, LiaO, 30, and its Hydrate, closely resemble the correspond- 
ing compounds of the two elements above described. They yield by 
union with acids the lithia-salts. 

Ru1>idiuiit, Rb, 85.5, and Cacisiiitni, Cs, 133,— Besides Potas- 
sium, Sodium, and Lithium, there are two other recently discovered 
alkali-metuls, viz. : Rubidium and Caesium. These elements are com- 
paratively rare, although they appear to be widely distributed in nature 
in minute quantity. 

Rubidium has been found in the ashes of tobacco and sugar-beet, as 
well as in commercial potash. Caesium, "which is the rarer of the two, 
has as yet not been detected in the ashes of plants, but undoubtedly oc- 
curs in them. These metals and their compounds have, in general, the 
closest similarity to the other alkali-metals. 

Alkaxi-earth Metals. — The two metallic elements 

next to be noticed, viz. : Calcium and Magnesium, give, 

with oxygen, the alJcall-earths, lime and magnesia. The 

metals are only procurable by difficult chemical processes, 

and from their eminent oxidability are not found in nature. 

They are but a little heavier than water. Their oxides are 

but slightly soluble in water. 

CALCIUM JSJSB ITS COMPOUNDS. 

Calcium, Ca, 40, is a brilliant ductile metal having a 
light yellow color. In moist air it rapidly tarnishes and 
acquires a coating of lime. 



126 HOW CEOPS GUOW. 

Lime; CaO, 56. — Is the result of the oxidation of cal- 
cium. It is prepared for use in the arts by subjecting 
limestone or oyster-shells to an intense heat, and usually 
retains the form and much of the hardness of the material 
from which it is made. It has the bitter taste and corrod- 
ing properties of the alkalies, though in a less degree. It 
is often called quick-lime, to distinguish it from its com- 
pound with water. It may occur in the ashes of plants 
when they have been maintained at a high heat after the 
volatile matter has been burned away. It is the base of 
the salts of lime. 

Hydrate of Lime, CaO, H,0, or CaH, O,, 74.— Quick- 
lime, when exposed to the air, gradually absorbs water 
and falls to a fine powder. It is then said to be air-slaked. 
When water is poured upon quick-lime it penetrates the 
pores of the latter, and shortly the falling to powder of 
the lime and the development of much heat, give evi- 
dence of chemical union between the lime and the water. 
This chemical combination is further proved by the in- 
crease of weight of the lime, 56 lbs. of quick-lime becom- 
ing 74 lbs. \)j water-sldking. On heating slaked lime to 
redness, its water may be expelled. 

When lime is agitated for some time with much water, 
and the mixture is allowed to settle, the clear liquid is 
found to contain a small amount of lime in solution (one 
part of lime to 700 parts of water). This liquid is called 
lime-water, and has already been noticed as a test for car- 
bonic acid. Lime-water has the alkaline taste in a marked 
degree. 

MxiGNESIUM AIH^D ITS COMPOIJJSrDS. 

Magnesium, Mg, 24 — ^Metallic magnesium has a silver- 
white color. When heated in the air it burns with ex- 
treme brilliancy (magnesium light), and is converted into 



THE ASH OF PLANTS. 127 

Magnesia, Mg O, 40, is the oxide of magnesium. It is 
found in the drug-stores in the shape of a bulky white 
powder, under the name of calcined magnesia. It is pre- 
pared by subjecting either hydrate, carbonate, or nitrate, 
of magnesia to a strong heat. It occurs in the ashes of 
plants. 

Hydrate of Magnesia, Mg O H^O, is produced slowly 
and without heat, when magnesia is mixed with water. It 
occurs as a transparent, glassy mineral (Brucite) at Texas, 
Penn., and a few other places. It readily absorbs carbonic 
acid, and passes into carbonate of magnesia. Hydrate of 
magnesia is so slightly soluble in water as to be tasteless. 
It requires 55,000 times its weight of water for solution, 
(Fresenius). 

Heavy Metals. — The two metals remaining to notice 
are Iron and Manganese. These again considerably re- 
semble each other, though they differ exceedingly from 
the metals of the alkalies and alkali-earths. They are 
about eight times heavier than water. Each of these 
metals forms two basic oxides, which are totally insoluble 
in pure water. 

IRON- AND ITS COMPOUNDS. 

Iron, Fe,* 56. — ^The properties of metallic iron are so 
well known that we need not occupy any space in reca- 
pitulating them. 

Protoxide \ of Iron, Fe O, 72. — ^When sulphuric acid 
in a diluted state is put in contact with metallic iron, hy- 
drogen gas shortly begins to escape in bubbles from the 
liquid, and the iron dissolves, uniting with the acid to form 
the protosulphate \ of iron, the salt known commonly as 
copperas or green-vitriol. 

* From the Latin name Ferrum. 

+ The prefix j9?'0< or proto, from the Greek, meaning ^r5<, is employed to dis- 
tinguish this oxide and its salts from the compounds to be subsequently de- 
scribed. 



128 HOW CROPS GROW. 

H,0, SO3, + Fe = Fe O, SO3 + H,. 
If, now, lime-water or potash-lye be added to the solu- 
tion of iron thus obtained, a white or greenish-whito pre- 
cipitate separates, Avhich is a hydrated protoxide of iron, 
(Fe 0,2 H^O). This precipitate rapidly absorbs oxygen 
from the air, becoming black and finally brown. The 
anhydrous protoxide of iron is black. Carbonate of 
protoxide of iron is of frequent occurrence as a mineral 
(spathic iron), and exists dissolved in many mineral wa- 
ters, especially in the so-called chalybeates. 

Sesquioxide of Iron,* Fe^ O3, 160.— When protoxide 
of iron is exposed to the air, it acquires a brown color from 
union with more oxygen, and becomes hydrated sesqui- 
oxide. The yellow or brown rust which forms on surfaces 
of metallic iron when exposed to moist air is the same 
body. Iron in the form of sesquioxide is found in the ashes 
of all agricultural plants, the other oxides of iron passing 
into this when exposed to air at high temperatures. It is 
found in immense beds in the earth, and is an important 
ore, (specular iron, haematite). It dissolves in acids, 
forming sesquisalts of iron, Avhich have a yellow color. 

Magnetic Oxide of Iron, Feg O4, or FcO, Fes O3, is a combination 
of the two oxides above mentioned. It is blaclv, and is strongly attract- 
ed by tlie magnet. It constitutes, in fact, the native magnet, or load- 
stone, and is a valuable ore of iron. 

MANGAXESE AND ITS COMPOUI^DS. 

Manganese, Mn, 55. — ^Metallic manganese is difficult to 
procure in the free state, and much resembles iron. Its 
oxides which concern the agriculturist are analogous to 
those of iron just noticed. 

Protoxide of Manganese, Mn O, 71, has an olive- 
green color. It is the base of all the usually occurring 



* The prefix sesqui {one and a half) is applied to those oxides in which the 
ratio of metal to oxygen is as one to one and a half, or, what is the same, as 
two to three. The above compound is also called peroxide of iron. 



THE ASH OF PLANTS. 129 

salts of manganese. Its hydrate, prepared by decompos- 
ing protosulphate of manganese by lime-water, is a white 
substance, which, on exposure to the air, shortly becomes 
brown and finally black from absorption of oxygen. The 
salts of protoxide of manganese are mostly pale rose-red 
in color. 

Sesqiiioxide of JVlang-a^ncse, Miia O3, occurs native as the 
mineral hraunite, or, combined Avith water, as manganite. It is a sub- 
stance having a red or black-brown color. It dissolves in cold acids, 
forming salts of an intensely red color. These are, however, easily de- 
composed by heat, or by organic bodies, into oxygen and i^rotosalts. 

Red Oxide of JVIang-aitese, Mng O4, or Mn O, Mna O3.— This 
oxide remains when manganese or any of its other oxides are subjected 
to a high temperature with access of air. The metal and the protoxide 
gain oxygen by this treatment, the higher oxides lose oxygen until this 
compound oxide is formed, which, as its symbol shows, corresponds to 
the magnetic oxide of iron. It is found in the ashes of plants. 

Black Oxide of Iflang^anese, Mn O2.— This body is found 
extensively in nature. It is employed in the preparation of oxygen and 
chlorine, (bleaching powder), and is an article of commerce. 

Some other metals occur as oxides or salts in ashes, though not in 
such quantity or la such plants as to possess any agricultural significance 
in this respect. 

Alumina, the sesquioxideof the metal Aluminum, is found in con- 
siderable quantity (20 to 50 per cent) in the ashes of the ground pine 
{Lycopodium). It is united with an organic acid {tartaric, according to 
Berzelius ; malic, according to Ritthausen) in the plant itself. It is often 
found in small quantity in the ashes of agricultural plants, but whether 
an ingredient of the plant or due to particles of adhering clay is not in 
all cases clear. 

Zinc has been found in a A^ariety of yellow violet that grows in the 
zinc mines of Aix la Chapelle. 

Copper is frequently present in minute quantity in the ash of trees, 
especially of such as grow in the vicinity of manufacturing establish- 
ments, where dilute solutions containing copper are thrown to waste. 

The salts or compounds of metals with non-metals 

found in the ashes of plants or in the unburned plant re- 
main to be considered. 

Of the elements, acids, and oxides, that have been no- 
ticed as constituting the ash of plants, it must be remark- 
ed that with the exception of silica, magnesia, oxide of 
6* 



130 HOW CROPS GROW. 

iron, and oxide of manganese, they all exist in the ash in 
the form of salts, (compounds of acids and bases). In the 
living agricultural plant it is probable, that of them all, 
only silica occurs in the uncombined state. 

We shall notice in the first place the salts which may 
occur in the ash of plants, and shall consider them under 
the following heads, viz. : Carbonates, Sulphates, Phos- 
phates, and Chlorides. As to the Silicates, it is unneces- 
sary to add anything here to what has been already men- 
tioned. 

The Carbonates which occur in the ashes of plants 
are those of Potash, Soda, and Lime. (Carbonate of 
Rubidia, similar to carbonate of soda, and Carbonate of 
Lithia, i-ather insoluble in water, may also be present, but 
in exceedingly minute quantity.) The Carbonates of Mag- 
nesia, Iron, and Manganese, are decomposed by the heat 
at which ashes are prepared. 

Carbonate of Potash, K^O CO^, 114.— The pearl-ash 
of commerce is a tolerably pure form of this salt. When 
wood is burned, the potash which it contains is found in 
the ash, chiefly as carbonate. If wood-ashes are repeat- 
edly washed or leached with water, all the salts soluble in 
this liquid are removed ; by boiling this solution down to 
dryness, which is done in large iron pots, crude potash is 
obtained, as a dark or brown mass. This, when somewhat 
purified, yields pearl-ash. Carbonate of potash, when pure, 
is white, has a bitter, biting taste — ^the so-called alkaline 
taste. It has such attraction for water, that, when expos- 
ed to the air, it absorbs moisture and becomes a liquid. 

If chlorhydric acid be poured upon carbonate of potash 
a brisk effervescence immediately takes place, owing to the 
escape of carbonic acid gas, and chloride of potassium and 
water are formed which remain behind. 

K,0 CO, + 2H CI = 2K CI + H^ + C0„. 

Bicarbonate of Potash, KHO CO,. — A solution of 



THE ASH OF PLANTS. 131 

carbonate of potash when exposed to carbonic acid gas 
absorbs the latter, and the bicarbonate of potash is pro- 
duced, so called because to a given amount of potassium 
it contains twice as much carbonic acid as the carbonate. 
P otash-salmratu^ consists essentially of this salt. It 
probably exists in the juices of various plants. 

Carbonate of Soda, Na.O CO^, 106. — This substance, so 
important in the arts, was formerly made from the ashes 
of certain marine plants (Salsola and Salicornia)^ in a man- 
ner similar to that now employed in wooded countries for 
the preparation of potash. It is at present almost wholly 
obtained from common salt by a somewhat complicated 
process. It occurs in commerce in an impure state under 
the name of Soda-ash. When nearly pure it forms sal- 
soda^ which usually exists in transparent crystals or crys- 
tallized masses. These contain 63 percent of water, which 
slowly escapes when the salt is exposed to the air, leaving 
the anhydrous (water-free) carbonate as a white, opaque 
powder. 

Carbonate of soda has a nauseous alkaline taste, not 
nearly so decided, however, as that of the carbonate of 
potash. It is often present in the ashes of plants. 

Bicarbonate of Soda, NaHO CO^. — The supercarhon- 
ate of soda of the apothecary is this salt in a nearly pure 
state. The soda-salmratiis of commerce is a mixture of 
this with some simple carbonate. It is prepared in the 
same way as the bicarbonate of potash. The bicarbonates, 
both of potash and soda, give off half their carbonic acid 
at a moderate heat, and lose all of this ingredient by con- 
tact with excess of any acid. Their use in baking depends 
upon these facts. They neutralize any acid (lactic or 
acetic) that is formed during the " rising " of the dough, 
and assist to make the bread " light " by inflating it with 
carbonic acid gas. 

Carbonate of Lime, CaO CO^, 112.— This compound is 



132 HOW CROPS GROW. 

the white powder formed by the contact of carbonic acid 
with lime-water. When hydrate of lime is exposed to the 
air, the water it contains is gradually displaced by car- 
bonic acid, and carbonate of lime is the result. Air- 
slaked lime always contains much carbonate. This salt 
is distinguished from hydrate of lime by its bein^ destitute 
of any alkaline taste. 

In nature carbonate of lime exists to an immense extent 
as coral, chalk, marble, and limestone. These rocks, when 
strongly heated, especially in a current of air, part with 
their carbonic acid, and quick-lime remains behind. 

Carbonate of lime occurs largely in the ashes of most 
plants, particularly of trees. In the manufacture of pot- 
ash, it remains undissolved, and constitutes a chief part 
of the residual leached ashes. 

The carbonate of lime found in the ashes of plants is 
supposed to come mainly from the decomposition by heat 
of organic salts of lime, (oxalate, tartrate, malate, etc.,) 
which exist in the juices of the vegetable, or are abun- 
dantly deposited in its tissues in the solid form. Carbonate 
of lime itself is, however, not an unusual component of 
vegetation, being found in the form of minute, rhombic 
crystals, in the cells of a multitude of plants. 

The Sulphates which we shall notice at length are 
those of Potash, Soda, and Lime. Sulphate of Magnesia 
is well known as ej^som salts, and Sulphate of Iron is 
copperas or green-vitriol. (Sulphate of Lithia is very 
similar to sulphate of potash.) 

Sulphate of Potash, K,0 SO3, 174.— This salt may be 
procured by dissolving potash or carbonate of potash in 
diluted sulphuric acid. On evaporating its solution, it is 
obtained in the form of hard, brilliant crystals, or as a 
white powder. It has a bitter taste. Ordinary potash, 
or pearl-ash, contains several per cent of this salt. 

Sulphate of Soda, ISTa.O S03, U2.— Glauber's salt is 



THE ASH OF PLANTS. 133 

the common name of this familiar substance. It has a 
bitter taste, and is much employed as a purgative for cat- 
tle and horses. It exists, either crystallized and transpar- 
ent, containing 10 molecules, or nearly 56 per cent, of 
water, or anhydrous. The crystals rapidly lose their water 
when exposed to the air, and yield the anhydrous salt as a 
white powder. 

Sulphate of Lime, CaO SO3, 136.— The burned Plaster 
of Paris of commerce is this salt in a more or less pure 
state. It is readily formed by pouring diluted sulphuric 
acid on lime or marble. It is found in the ash of most 
plants, especially in that of clover, the bean, and other 
legumes. 

In nature, sulphate of lime is usually combined with 
two molecules of water, and thus constitutes Gypsum^ 
CaO SO3 SHjO, which is a rock of frequent and extensive 
occurrence. In the cells of many plants, as for instance 
the bean, gypsum may be discovered by the microscope 
in the shape of minute crystals. It requires 400 times its 
weight of water to dissolve it, and being almost univer- 
sally distributed in the soil, is rarely absent from the^water 
of wells and springs. 

The Phosphates which require special description are 
those of Potash, Soda, and Lime. 

There exist, or may be prepared artificially, numerous 
phosphates of each of these bases. The chemist is ac- 
quainted with no less than thirteen different phosj^hates of 
soda. But three classes of phosphates have any immedi- 
ate interest to the agriculturist. As has been stated (p. 
117), hydrated phosphoric acid prepared by boiling anhy- 
drous phosphoric acid with water, is represented by the 
symbol SH^O, P^O^. The phosphates may be regarded as 
hydrated phosphoric acid in which one, two, or all the 
molecules of water are substituted by the same number 
of molecules of one or of several bases. We may illus- 



134 HOW CEOPS GROW. 

tr.ite this statement with the three phosphates of lime, 
giving in one view their mode of derivation, their sym- 
bols, and the names which we shall employ in this treatise. 

a.— 3 H,0, P,0, and CaO give H,0 and 2 H,0, CaO, 
P^Og, the monocalcic* phosphate or acid-phosphate of 
lime. 

b.—3 H,0, P,0, and 2 CaO give 2 H,0 and 11,0, 2 Ca 
O PgOg, the dicalcic * phosphate or neutral phosphate of 
lime. 

e.~S H,0, P,0, and 3 CaO give 3 H,0 and 3 CaO P, 

O^, the tricalcic * j^hosjDhate or basiophosphate of lime. 

Phosphates of Potash. — Of these salts, the neutral and 
subphosphates exist largely (to the extent of 40 to 50 per 
cent) in the ash of the kernels of wheat, rye, maize, and 
other bread grains. N^one of these phosphates occur in 
commerce ; they closely resemble the corresponding soda- 
salts in their external characters. 

Phosphates of Soda. — Of these the disodic, or neutral 
phosphate, 2 Na^O, H^O, P^O^ + 12 Aqf, alone needs no- 
tice. It is found in the drug-stores in the form of glassy 
crystals, which contain 12 molecules (56 per cent) of water. 
The crystals become opaque if exposed to the air, from the 
loss of water. This salt has a cooling, saline taste, and is 
very soluble in water. 

Phosphates of Lime* — Both the neutral and subphos- 
phate of lime probably occur in plants. The neutral or 
dicalcic salt, (2 CaO H^O, P^O^ + 2 Aq), is a white crys- 
talline powder, nearly insoluble in water, but easily soluble 
in acids. In nature it is found as a urinary concretion in 



* These names indicate the proportions of acid and base in the compounds, 
and may be translated into common English, thus : One-lime ^^AospAaie, two-lime 
phosphate^ and three-lime phosphate respectively. 

t The water which is found in crystallized salts and which usually may be ex- 
pelled at a gentle heat, is termed tvater of crystallization, and is often designated 
by Aq., (from the Latin Aqua), to distinguish it from basic ivater, Avhich is more 
intimately combined. 



THE ASH OF PLANTS. 135 

the sturgeon of the Caspian Sea. It is also an ingredient 
of guanos, and probably of animal excrements in general. 
The tricalcic phosphate, or, as it is sometimes termed, 
the hone-phosphate, 3 CaO, PjO^, is a chief ingredient of 
the bones of animals, and constitutes 90 to 95 per cent of 
the ash or earth of bones. It may be formed by adding a 
solution of lime to one of phosphate of soda, and appears 
as a white precipitate. It is insoluble in pure water, but 
dissolves in acids and in solutions of many salts. In the 
mineral kingdom tricalcic phosphate is the chief ingredient 
of apatite savdi phosphorite. These minerals are employed 
in the preparation of the so-called superphosphate of lime, 
which is consumed to an enormous extent as a turnip-fer- 
tilizer. The superphosphate of commerce, when genuine, 
is essentially a mixture of sulphate of lime with the three 
phosphates above noticed, of which the monocalcic phos- 
phate should predominate. 

The Phosphates of Magnesia, Iron, and Manganese, 
are bodies insoluble in water, and require no particular 
notice. 

The Chlorides are all characterized by their ready solu- 
bility in water. The chlorides of Lithium, Calcium, and 
Magnesium, are deliquescent, i. e., they liquefy by absorb- 
ing moisture from the air. The chlorides of Potassium 
and Sodium alone need to be described. 

Chloride of Potassium, K CI, 74.5.— This body may be 
produced either by exposing metallic potassium to chlorine 
gas, in which case the two elements unite together direct- 
ly ; or by dissolving caustic potash in chlorhydric acid. 
In the latter case water is also formed, as is expressed by 
the equation K HO + H CI = K CI + H,0. 

Chloride of potassium closely resembles common salt 
(chloride of sodium) in appearance, solubility in water, 
taste, etc. It is but.rarely an article of commerce, but is 
present in the ash and in the juices of plants, especially of 
sea-weeds, and is likewise found in all fertile soils. 



136 HOW CROPS GROW. 

Chloride of Sodium, Na CI, 58.5 — This substance is 
common or cnlinary salt. It was formerly termed muriate 
of soda. It is scarcely necessary to speak of its occur- 
rence in immense quantities in the water of the ocean, in 
saline springs, and in the solid form as rock-salt, in the 
earth. Its properties are so familiar as to require no de- 
scription. It is rarely absent from the ash of plants. 

Besides the salts and compounds just described, there 
occur in the living plant other substances, most of which 
have been indeed already alluded to, but may be noticed 
again connectedly in this place. 

These compounds, being destructible by heat, do not 
appear in the analysis of the ash of a plant. 

Nitrates : JVitric acid — the compound by which nitro- 
gen is chiefly furnished to plants for the elaboration of the 
albuminoid principles — is not unfrequently present as a 
nitrate in the tissues of the plant. It usually occurs there 
as Nitrate of Potash, (niter, saltpeter.) 

The properties of this salt scarcely need description. It 
is a white, crystalline body, readily soluble in water, and 
has a cooling, saline taste. When heated with carbonaceous 
matters, it yields oxygen to them, and a deflagration, or 
rapid and explosive combustion, results. Touch-paper is 
paper soaked in solution of niter, and dried. The leaves 
of the sugar-beet, sun-flower, tobacco, and some other 
plants, have been found to contain this salt. When sucli 
vegetables arc burned, the nitric acid is decomposed, often 
with slight deflagration, or glowing like touch-paj^er, and 
the alkali remains in the ash as carbonate. The characters 
of nitric acid and the nitrates will be noticed at length in 
another volume, " How Crops Feed." 

Oxalates, Citrates, Malates, Tartrates, and salts of 
other less common organic acids, are generally to be found 
in the tissues of living plants. On burning, the bases with 
Avhich they were in combination — potash and lime in most 
cases — remain as carbonates. 



THE ASH OF PLANTS. 137 

Salts of Ammonia exist in minute amount in some 
plants. What particular salts thus occur is uncertain, and 
special notice of them is unnecessary in this chapter. 

Since it is possible for each of the acids above described 
to unite with each of the bases in one or several propor- 
tions, and since we have as many oxides and chlorides as 
there are metals, and even more, the question at once 
arises — which of the 60 or more compounds that may thus 
be formed outside the plant, do actually exist witliin it ? 
In answer, we must remark that all of them may exist in 
the plant. Of these, however, but few have been proved 
to exist as such in the vegetable organism. As to the 
state in which iron and manganese occur, we know little or 
notliing, and we cannot assert positively that in a given 
plant potash exists as phosphate, or sulphate, or carbonate. 
We judge, indeed, from the predominance of potash and 
phosphoric acid in the ash of wheat, that phosphate of pot- 
ash is a large constituent of the grain, but of this we are 
not sure, though m the absence of evidence to the contrary 
we are warranted in assuming these two ingredients to be 
united. On the other hand, carbonate of lime and sul- 
phate of lime have been discovered by the microscope in 
the cells of various plants, in crystals whose characters 
are unmistakeable. 

For most purposes it is unnecessary to know more than 
that certain elements are present, without paying atten- 
tion to their mode of combination. And yet there is choice 
in the manner of representing the composition of a plant 
as reo^ards its ash-in ojredients. 

We do not, indeed, speak of the calcium or the silicon in 
the plant, but of lime and silica, because the idea of these 
rarely seen elements is much more vague, except to the 
chemist, than that of their oxides, with which every one 
is familiar. 

Again, we do not speak of the sulphates or chlorides, 



138 HOW CEOPS GROW. 

when we desire to make statements which may be com- 
pared together, because, as has just been remarked, we 
cannot always, nor often, say what sulphates or what 
chlorides are present. 

In the paragraphs that follow, which are devoted to 
a more particular statement of the mode of occurrence^ 
relative cibundance^ special function, and indlspensahility 
of the fixed ingredients of plants, will be indicated the 
customary and best method of defining them. 

§ 2- 

QUANTITY, DISTRIBUTION, AND VARIATIONS OF THE ASH- 
INGREDIENTS. 

The ash of plants consists of the various fixed acids, 
oxides, and salts, noticed in § 1. 

The ash-ingredients are always present in each cell of 
every plant. 

The ash-ingredients exist partly in the cell-wall, in- 
crusting or imbedded in the cellulose, and partly in the 
plasma or contents of the cell, (see p. 224.) 

One portion of the ash-ingredients is soluble in water, 
and occurs in the juice or sap. This is true, in general, 
of the salts of the alkahes, and of the sulphates and 
chlorides of magnesium and calcium. Another portion is 
insoluble, and exists in the tissues of the plant in the 
solid form. Silica, the phosphates of lime, and the mag- 
nesia compounds, are mostly insoluble. 

The ash-ingredients may be separated from the volatile 
matter by burning or by any process of oxidation. In 
burning, portions of sulphur, chlorine, alkalies, and phos- 
phorus, may be lost under certain circumstances, by vola- 
tilization. The ash remains as a skeleton of the plant, 
and often actually retains and exhibits the microscopic 
form of the tissues. 

The Proportion of Ash is not inyariahle, even in the 



i 



THE ASH OF PLANTS. 



139 



same kind of plant, and in the same part of the plant. 
Different kinds of plants often manifest very marked differ- 
ences in the quantity of ash they contain. The following 
table exhibits the amount of ash in 100 parts, (of dry mat- 
ter^ of a number of plants and trees, and in their several 
parts. In all cases is given the average proportion, as de- 
duced from a large number of the most trustworthy exam- 
inations. In some instances are cited the extreme propor- 
tions hitherto put on record. 

PROPORTIONS OF ASH IN VARIOUS VEGETABLE MATTERS. 

ENTIRE TLATSTTS, BOOTS EXCEPTED. 



Red clover 6.7 

White " 7.2 

Timoth}^ 7.1 

Potatoes 5.1 

Sugar beet, 16.3— 18. G 17.5 

Field beet, 14.0—21.8 18.2 



average 

Turnips, 10.7—19.7 15.5 

Carrot, 15.0-21.3 17.1 

Hops 9.9 

Hemp 4.6 

Flax 4.3 

Heath. 4.5 



ROOTS ANB TUBERS. 



Turnip, 6.0—20.9 12.0 

Carrot, 5.1—10.9 8.2 

Artichoke 5.2 



Potato, 2.6-8.0 4.1 

Sugar beet, 2.9—6.0 4.4 

Field beet, 2.8—11.3 7.7 

STRAW AND STEMS. 

Wheat, 3.8-6.9 5.4 I Peas, 6.5—9.4 7.9 

Rye, 4.9—5.6 5.3 | Beans, 5.1—7.2 6.1 

Oats, 5.0^.4 5.3 Flax .- 3.7 

Barley. . .* 6.8 | Maize 5.5 

GRAINS AND SEED. 



Wheat, 1.5—3.1 2.0 

Rye, 1.6—2.7 2.0 

Oats, 2.5— 4.0 3.3 

Barley, 1.8— 2.8 2.3 

Maize, 1.3—2.1 1.5 

WOOD. 



Buckwheat, 1.1—2.1 1.4 

Peas, 2.4—2.9 2.7 

Beans, 2.7—4,3 3.7 

Flax 3.6 

Sorghum 1.9 



Beech .1.0 

Birch 0.3 

Grape '...2.7 

Apple 



.1.3 



Red Pine 0.3 

White Piuc 0.3 

Fir.. 0.3 

Larch 0.3 



Birch 1.3 

Red pine 2.8 

White pine 3.3 



Fir 2.0 

Walnut .6.4 

Cauto tree 34.4 



140 HOW CEOPS GEOW. 

From the above table we gather : — 

1. That different plants yield different quantities of ash. 
It is abundant in succulent foliage, like that of the beet, 
(18 per cent,) and small in seeds, wood, and bark. 

2t That different parts of the same plant yield unlike 
proportions of ash. Thus the wheat kernel contains 2 per 
cent, while the straw yields 5.4 per cent. The ash in su- 
gar-beet tops is 17.5 ; in the roots, 4.4 per cent. In the 
ripe oat, Arendt found {Das Wachsthum der Hafer- 
pflanze^ p. 84,) 

Iq the three lower joints of the stem 4.6 per cent of ash 

In the two middle joints of the stem 5.3 " " 

In the one upper joint of the stem 6.4 " " 

In the three lower leaves 10.1 " " 

In the two upper leaves 10.5 " " 

In the ear 2.6 " " 

3. We further find, that in general^ the upper and outer 
parts of the plant contain the most ash-ingredients. In 
the oat, as we see from the above figures of Arendt, the ash 
increases from the lower portions to the upper, until we 
reach the ear. If, however, the ear be dissected, we shall 
find that its outer parts are richest in ash. Norton found 

In the husked kernels of brown oats. . . . 2.1 per cent of ash 

In the husk of brown oats 8.2 " ^' 

In the chaff of brown oats 19.1 " " 

Norton also found that the top of the oat-leaf gave 16.22 
per cent of ash, while the bottom yielded but 13.66 per 
cent. {Am. Jour. Science, Vol. 3, 1847.) 

From the table it is seen that wood, (0.3 to 2.7 per cent,) 
and seeds, (1.5 to 3.7 per cent,) (lower or inner parts of 
the plant,) are poorest in ash. The stems of herbaceous 
plants, (3.7 to 7.9 per cent,) are next richer, while the 
leaves of herbaceous plants, which have such an extent of 
surface, are the richest of all, (6 to 8 per cent.) 

4. Investigation has demonstrated further that the same 
plant in different stages of growth varies in the propor- 



THE ASH OF PLANTS. 



141 



tions of ash in dry matter, yielded both by the entire 
plant and by the several organs or parts, 

The followin 
ijlustrate this 

parts of the oat-plant at intervals of one week throughout 
its entire period of growth. He found : 



J, results, obtained by Norton, on the oat, 
variation. Norton examined the various 



Knots. Chaff. Grain unlmsJced. 



Leaves. Stem. 

June 4 10.8 10.4 

June 11 ..10.7 9.8 

June 18 9,0 9.3 

June 25 10.9 9.1 

July 2 11.3 7.8 .. .. 4.9 

July 9 12.2 7.8 .. .. 4.3 

July 16 12.6 7.9 .. 6.0 3.3 

July 23 16.4 7.9 10.0 9.1 3.6 

July 30 16.4 7.4 9.6 12.2 4.2 

Au<,^ 6 16.0 7.6 10.4 13.7 4.3 

Au^. 13 20.4 6.6 10.4 18.6 4.0 

Aug. 20 21.1 . 6.6 11.7 21.0 3.6 

Aug. 27 22.1 7.7 11.2 22.4 3.5 

Sept. 3 20.9 8.3 10.7 27.4 3.6 

Here, in case of the leaves and chaff, we observe a con- 
stant increase of ash, while in the stem there is a constant 
decrease, except at the time of ripening, when these rela- 
tions are reversed. The knots of the stem preserved a 
pretty uniform ash-content. The unhusked grain at first 
suffered a diminution, then an increase, and lastly a de- 



Arendt found in the oat-plant fluctuations, not in all re- 
spects accordant with those observed by Norton. Arendt 
obtained the following proportions of ash ; 



3 lower 


2 middle 


Upper 


Lower 


Upper 


Ears. 


Entire 


joints of joints of joint of 


leaves. 


leaves. 




plant. 


stem. 


stem. 


ston. 










June 18.... 4.4 


.. 


,. 


9.7 


7.7 




8.0 


June 30.... 2.5 


2.9 


3.5 


9.4 


7.0 


3.8 


5.2 


July 10.... 3.5 


4.7 


5.2 


10.2 


6.9 


3.6 


5.4 


July 21.... 4.4 


5.0 


5.5 


10.1 


9.7 


2.8 


5.2 


July 31.... 6.4 


5.3 


6.4 


10.1 


10.5 


2.6 


5.1 



Here we see that the ash increased in the stem and in 
each of its several parts after the first examination. The 



143 HOW CEOPS GROW. 

lower leaves exhibited an increase of fixed matters after 
the first period, while in the upper leaves the ash dimin- 
ished toward the third pei'iod, and thereafter increased. In 
the ears, and in the entire plant, the ash decreased quite 
regularly as the plant grew older. Pierre found that the 
proportion of ash of the colza, {Srassica oleracea^ dimin- 
ished in all parts of the plant, (which was examined at five 
periods,) except in the leaves, in which it increased. 
{Jahreshericht uher Agriculturchemie, III, p. 122.) The 
sugar beet, (Bret Schneider,) and potato, (Wolff,) exhibit 
a decrease of the per cent of ash, both in tops and roots. 

In the turnip, examined at four periods, Anderson, 
{Trans. High, and Ag. jSoc, 1859—61,^. 371,) found the 
following per cent of ash in dry matter: 

Juhj 7. Aug. 11. Sept. 1. Oct. 5. 

Leaves 7.8 20.6 18.8 16.2 

Bulbs 17.7 8:7 10.2 20.9 

In this case, the ash of the leaves increased during about 
half the period of growth from 7.8 to 20.6, and thence di- 
minished to 16.2. The ash of the bulbs fluctuated in the re- 
verse manner, falling from 17.7 to 8.7, then rising again to 
20.9. 

J?i general., the proportloyi of ash of the entire plant 
diminishes regularly as the plant grows old. 

5. The influence of the soil in causing the proportion of 
ash of the same kind of plant to vary, is shown in the fol- 
lowing results, obtained by Wunder, ( Yersuchs-Stationen^ 
JV, p. 266,) on turnip bulbs, raised during two successive 
years, in different soils. 

lu sandy soil. In loamy soil. 

Id year. 2d year. 1st year. 2d year. 
Per cent of ash.... 13.9 11.3 9.1 10.9 

6. As might be anticipated, different varieties of the 
same plant, grown on the same soil, take up different 
quantities of non-volatile matters. 

In five varieties of potatoes, cultivated in the same soil 



THE ASH OF PLANTS. 143 

and under the same conditions, Herapath, {Qu, Jour. 
Ghem. Soc, II, p. 20,) found the percentages of ash in 
dry matter of the tuber as follows : 

Variety of potato. White Prince's Axbridge Magpie. Forty- 
Apple. Beauty. Kidney. fold. 
Ash per cent 4.8 3.6 4.3 3.4 3.9 

7t It has been observed further that different individuals 
of the same variety of plant., growing side by side, on the 
same soil, (in the same field at least,) contain different pro- 
portions of ash-ingredients, according as they are, on the 
one hand, healthy., vigorous plants., or, on the other, weah 
and stU7ited. Pierre, {Jahreshericht uber Agricidturchemie, 
III,^. 125,) found in entire colza plants of various degrees 
of vigor the following percentages of ash in dry matter : 

In extremely feeble plants, 1856 8.0 per cent of ash 

In very feeble plants, 1857. 9.0 " " 

In feeble plants, 1857 11.4 " " 

In strong plants, 1857 11.0 " •' 

In extremely strong plants, 1857 14.3 " ' '•' 

Pierre attributes the larger per cent of asli in the strong 
plants to the relatively greater quantity of leaves devel- 
oped on them. 

Similar results were obtained by Arendt in case of oats. 
Wunder, ( VersuchsSt., IV, p. 115,) found that the leaves 
of small turnip plants yielded somewhat more ash, per 
cent, than large plants. The former gave 19. T, the latter 
16.8 per cent. 

8. The reader is prepared from several of the foregoing 
statements to understand partially the cause of the varia- 
tions in the proportion of ash in different specimens of the 
same kind of plant. 

The fact that different parts of the plant are unlike in 
their composition, the upper and outer portions being, in 
general, the richer in ash-ingredients, may explain in some 
degree why different observers have obtained different 
analytical results. 

It is well known that a variety of circumstances in- 



144 HOW CEOPS GEOW. 

fluences the relative development of the organs of a plant. 
In a dry season, plants remain stunted, are rougher on the 
surface, have more and harsher hah's and prickles, if these 
belong to them at all, and develope fruit earlier than 
otherwise. In moist weather, and under the influence of 
rich manures, plants are more succulent, and the stems and 
foliage, or vegetative parts, grow at the expense of the re- 
productive organs. Again, different varieties of the same 
plant, which are often quite unlike in their style of devel- 
opment, are of necessity classed together in our table, and 
under the same head are also brought together plants 
gathered at different stages of growth. 

In order that the wheat plant, for example, should always 
have the same percentage of ash, it would be necessary 
that it should always attain the same relative development 
in each individual part. It must, then, always grow under 
the same conditions of temperature, light, moisture, and 
soil. This is, however, as good as impossible, and if we 
admit the wheat plant to vary in form within certain lim- 
its without losing its proper characteristics, we must ad- 
mit corresponding variations in composition. 

The difference between the Tuscan wheat, which is cul- 
tivated exclusively for its straw, of which the Leghorn 
hats are made, and the "pedigree wheat" of Mr. Hallett, 
{Journal JRoy. Ag. Soc. of Eng.^ Vol 22^ p. 374,) is in some 
respects as great as between two entirely different plants. 
The hat wheat has a short, loose, bearded ear, containing 
not more than a dozen small kernels, while the pedigree 
wheat has shown beardless ears of 8| inches in length, 
closely packed with large kernels to the number of 120 ! 

]^ow, the hat wheat, if cultivated and propagated in the 
same careful manner as has been done with the pedigree 
wheat, Avould, no doubt, in time become as prolific of grain 
as the latter, while the pedigree wheat might perhaps with 
greater ease be made more valuable for its straw than its 
grain. 



THE ASH OP PLANTS. 145 

We easily see then, that, as circumstances are perpetual- 
ly making new varieties, so analysis continually finds di- 
versities of composition. 

9. Of all the parts of plants the seeds are the least liable 
to vary in composition. Two varieties or two individuals 
may differ enormously in their relative proportions of 
foliage, stem, chaff, and seed ; but the seeds themselves 
nearly agree. Thus, in the analyses of 67 specimens of 
the wheat kernel, collated by the author, the extreme 
percentages of ash were 1.35 and 3.13. In 60 specimens 
out of the 67, the range of variation fell between 1.4 and 
2.3 per cent. In 42 the range was from 1.7 to 2.1 per 
cent, while the average of the whole was 2.1 per cent. 

In the stems or straw of the grains, the variation is much 
more considerable. Wheat-straw ranges from 3.8 to 6.9 ; 
pea-straw, from 6.5 to 9.4 per cent. In fleshy roots, the 
variations are great ; thus turnips range from 6 to 21 per 
cent. The extremest variations in ash-content are, how- 
ever, found, in general, in the succulent foliage. Turnip 
tops range from 10.7 to 19.7; potato tops vary from 11 to 
near 20, and tobacco from 19 to 27 per cent. 

Wolff, (Die 7iaturgesetzlichen Grundlagen des Acker- 
haues, 3. Aufl., p. 117,) has deduced from a large number 
of analyses the following averages for three important 
classes of agricultural plants, viz.: 

Grain. Straw. 

Cereal crops 3 5.25 per cent. 

Leguminous crops 3 5 " " 

Oil-plants 4 4.5 " " 

• More general averages are as follows, (Wolff ?oc. cit.) : 



Annual and h iennial plants. 
Seeds - - - 3 per cent 
Stems - - - - 5 " '' 
Roots . - - 4 " " 
Leaves - . - 15 " " 
7 



Perennial plants. 
Seeds - - - 3 per cent 
Wood- - - - 1 " " 
Bark - - - 7 " " 
Leaves - - - 10 " *' 



146 HOW CROPS GROW. 

We may conclude this section by stating three proposi- 
tions which are proved in part by the facts that have been 
already presented, and which are a summing up of the 
most important points in our knowledge of this subject. 

I. Ash-ingredients are indispensable to the life and 
growth of all plants. In mold, yeast, and other plants of 
the simplest kind, as well as in those of the higher orders, 
analysis never fails to recognize a proportion of fixed mat- 
ters. "We must hence conclude that these are necessary to 
the primary acts of vegetation, that atmospheric food can- 
not be assimilated, that vegetable matter cannot be organ- 
ized, except with the cooperation of those substances, which 
are found in the ashes of the plant. This proposition is 
demonstrated further in the most conclusive manner by 
numerous synthetic experiments. It is, of course, impos- 
sible to attempt producing a plant at all without some ash- 
ingredients, for the latter are present in all seeds, and dur- 
ing germination are transferred to the seedling. By caus- 
ing seeds to sprout in a totally insoluble medium, we can 
observe what happens when the limited supply of fixed 
matters in the seeds themselves is exhausted. Wiegmann 
& Polstorf, {Preisschrift ilher die unorganischen Bestand- 
theile der Pflanzen^) planted 30 seeds of cress in fine plati- 
num wire contained in a platinum vessel. The contents 
of the vessel were moistened with distilled water, and the 
whole was placed under a glass shade, which served to 
shield from dust. Through an aperture in the shade, con- 
nection was made with a gasometer, by which the atmos- 
phere in the interior could be renewed with an artificial mix ■ 
ture, consisting in 100, of 21 parts oxygen,78 parts nitrogen, 
and 1 part carbonic acid. In two days .28 of the seeds 
germinated ; afterwards they developed leaves, and grew 
slowly with a healthy appearance during 26 days, reaching 
a height of two to three inches. From this time on, they 
refused to grow, began to turn yellow, and died down* 
The plants were collected, and burned ; the ash from them 



THE ASH OF PLANTS. 147 

weighed precisely as much as that obtained by burning 28 
seeds like those originally sown. This experiment demon- 
strates most conclusively that a plant cannot grow in the 
absence of those substances found in its ash. The devel- 
opment of the cresses ceased so soon as the fixed matters 
of the seed had served th^ir utmost in assisting the organ- 
ization of new cells. We know from other experiments 
that, had the ashes of cress been applied to the plants in 
the above experiment, just as they exhibited signs of un- 
healthiness, they would have recovered, and developed to 
a much greater extent. 

II. The proportion of ash-ingredients in the plant is va- 
riable within a narrovj range ; hut cannot fall below or 
exceed certain limits. The evidence of this proposition is to 
be gathered both from the table of ash-percentages, and 
from experiments like that of Wiegmann & Polstorf above 
described. 

Hit TFe have Reason to believe that each part or organ^ 
{each cell,) of the plant contains a certain, nearly invari- 
able amount of fixed matters, which is indispensable to the 
vegetative functions. Each part or organ may contain, he- 
S'ides, a variable and unessential or accidental quantity of 
the same. What portion of the ash of any plant is essen- 
tial and what accidental is a question not yet brought 
to a satisfactory decision. By assuming the truth of this 
proposition, we account for those variations in the amount 
of ash which cannot be attributed to the causes already 
noticed. The evidences of this statement must be reserv- 
ed for the subsequent section. 

§ 3. 

SPECIAL COMPOSITION OF THE ASH OF AGRICULTURAL 
PLANTS. 

The results of the extended inquiries which have been 
recently made into the subject of this section may be con- 



148 HOW CEOPS GEOW. 

veniently presented and discussed under a series of propo- 
sitions, viz.: 

1. Among the substances which have been described, 
(§ 1,) as the ingredients of the 2,'^^t'lie following are in- 
variably present in all agricultural plants^ and in nearly 
all parts ofthein^ viz.: 

C Potasli f Chlorine 

Soda Sulphuric acid 

Bases \ Lime Acids \ Phosphoric acid 
I Magnesia Silicic acid 

1^ Oxide of iron \ Carbonic acid 

2. Different normal specimens of the same hind of plant 
have a nearly constant composition. The use of the word 
nearly in the above statement implies what has been al- 
ready intimated, viz., that some variation is noticed in the 
relative proportions, as well as in the total quantity, of 
ash-ingredients occurring in plants. This point will 
shortly be discussed in full. By taking the average of 
many trustworthy ash-analyses, we arrive at a result 
which does not differ very widely from the majority of the 
individual analyses. This is especially true of the seeds 
of plants, which attain nearly the same development under 
all ordinary circumstances. It is less true of foliage and 
roots, whose dimensions and character vary to a great ex- 
tent. In the following tables (p. 150-156) is stated the com- 
position of the ashes of a number of agricultural products, 
which have been repeatedly subjected to analysis^ In 
most cases, instead of quoting all the individual analyses, 
a series of averages is given. Of these, the first is the 
mean of all the analyses on record or obtainable by the 
writer,* while the subsequent ones represent either the re- 
sults obtained in the examination of a number of samples 
by one analyst, or are the mean of several single anal- 



* The nnmerous ash-analyses, published hy Br, E. Emmons and Dr. J. H. 
Salisbury, in the Natural History of New York, and in the Trans, of the N. Y. 
State Ag. Society have been disregarded on account of their manifest worthless- 
ness and absurdity. 



THE ASH OF PLANTS. 149 

yses. In this way, it is believed, the real variations of 
composition are pretty truly exhibited, independently of 
the errors of analysis. 

The lowest and highest percentages are likewise given. 
These are doubtless in many cases exaggerated by errors 
of analysis, or by impurity of the material analyzed. 
Chlorine and sulphuric acid are for the most part too low, 
because they are liable to be dissipated in combustion, 
while silica is often too high, from the fact of sand and soil 
adhering to the plant. 

In two cases, single and perhaps incorrect analyses by 
Bichon, which give exceptionally large quantities of soda, 
are cited separately. 

A number of analyses that came to notice after making 
out the averages, are given as additional. 

The following table includes both the kernel and straw 
of Wheat, Eye, Barley, Oats, Maize, Rice, Buckwheat, 
Beans, and Peas ; the tubers of Potatoes ; the roots and 
tops of Sugar Beets, Field Beets, Carrots, Turnips, and 
various parts of the Cotton Plant. 

For the average composition of other plants and vege- 
table products, the reader is referred to a table in the ap- 
pendix, p. 376, compiled by Prof Wolff, of the Royal 
Agrieultural Academy of Wurtemberg. That table in- 
cludes also the averages obtained by Prof Wolff for most of 
the substances, cotton excepted, whose composition is rep- 
resented in the pages immediately following. Any dis- 
crepancies between Prof. Wolff's and the author's figures 
are for the most part due to the use of fewer analyses by 
the former. 

In both tables, the carbonic acid^ which occurs in most 
ashes, is excluded, from the fact that its quantity varies 
according to the temperature at which the ash is pre- 
pared. 



150 



HOW CROPS GROW. 



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THE ASn OF PLANTS. 



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153 



HOW CEOPS GEOW. 









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: CO eo' -*' tri TjJ ; : •inedd*t>s 



THE ASH OF PLANTS. 



153 



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154 



HOW CKOPS GEOW. 












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THE ASH OF PLANTS. 



155 



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Highest 


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156 



HOW CEOPS GROW. 



















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THE ASH OF PLANTS. 157 

The composition of the ash of a number of ordinary- 
crops is concisely exhibited in the subjoined general 
statement. 

Cereals— 

Grain*.... 30 12 3 46 2 2.5 1 

straw , 13—27 3 7 5 50--70 2.5 2 

Legumes — 

Kernel.... 44 7 5 35 1 4 2 

Straw 27—41 7 25—39 8 5 2-6 &-7 

EooT Ckops— 

Roots 60 3—0 6—12 8—18 1—4 5—12 3—9 

Tops 37 3—16 10—35 3—8 3 6—13 5—17 

Grasses — 

In flower.. 33 4 8 8 35 4 5 

3* Different parts of any plant usually exhibit decided 
differences in the composition of their ash. This fact is 
made evident by a comparison of the figures of the table 
above, and is more fully illustrated by the following anal- 
yses of the parts of the mature oat-plant, by Arendt, 1 to 6, 
{Die Haferpflanze^p. 107,) and Norton, 7 to 9, {Am. Jour. 
Set., 2 8er. 3, 318.) 

12 3 456789 

Lower Middle Upper Lower Upper Ears. Chaff. Husk.Kernel 

Stem. Stem. Stem. Leaves. Leaves. ' husked. 

Potash 81.2 68.3 55.9 36.9 24.8 13.0 I .-. r io 4 qi 7 

Soda 0.4' 1.5 1.0 0.9 0.4 0.1 T"-'^ ^'^'^ '^^•' 

Magnesia 2.1 3.6 3.9 3.8 3.9 8.9 "1 2.3 8.6 

Lime 3.6 5.3 8.6 16.7 17.2 7.3 '.. „ 4.3 5.3 

Oxide oflron 1.0 0.0 0,2 2.7 0.5 trace p^'^ 0.3 0.8 

Phosplioric acid 2.7 1.4 2.7 1.7 1.5 36.5 J 0.6 49.1 

Sulphuric acid 0.0 1.3 1.1 3.2 7.5 4.9 5.3 4.3 0.0 

Silica 4.1 9.3 20.4 34.0 41.8 26.0 68.0 74.1 1.8 

Chlorine 8.6 11.7 7.4 1.6 2.4 3.8 3.1 1.4 0.2 

The results of Arendt and Norton are not in all respects strictly com- 
parable, having been obtained by different methods, but serve well to 
establish the fact in question. 

We see from the above figures that the ash of the lower 
stem consists chiefly of potash, (81 °\^.) This alkali is pre- 
dominant throughout the stem, but in the upper parts, 
where the stem is not covered by the leaf sheaths, silica 
and lime occur in large quantity. In the ash of the leaves, 

* Exclusive of husk. 



158 HOW CEOPS GROW. 

silica, potash, and lime, are the principal ingredients. In 
the chaff and husk, silica constitutes three-fourths of the 
ash, while in the grain, phosphoric acid appears as the 
characteristic ingredient, existing there in connection with 
a large amount of potash, (32 "I „,) and considerable mag- 
nesia. Chlorine acquires its maximum, (11.7 "I „,) in the 
middle stem, but in the kernel is present in small quantity, 
while sulphuric acid is totally wanting in the lower stem, 
and most abundant in the upper leaves. 

Again, the unequal distribution of the ingredients of 
the ash is exhibited in the leaves of the sugar beet, which 
have been investigated by Bretschneider, {JBCoff. Jahreshe- 
richt^ 4, 89.) This experimenter divided the leaves of 6 
sugar beets into 5 series or circles, proceeding from the 
outer and older leaves inward. He examined each series 
separately with the following results : 

I. n. III. IV. v. 

Potash 18.7 25.9 32.8 37.4 50.3 

Soda 15.2 14.4 15.8 15.G 11.1 

Chloride of Sodium... 5.8 6.4 5.8 6.0 6.5 

Lime 24.2 19.2 18.2 15.8 4.7 

Magnesia 24.5 22.3 13.0 8.9 6.7 

Oxide of Iron 1.4 0.5 0.6 0.6 0.5 

Phosphoric acid 3.3 4.8 5.8 8.4 12.7 

Sulphuric acid 5.4 5.6 5.6 5.2 5.9 

Silica 1.5 0.8 2.7 2.1 1.5 

From these data we perceive that in the ash of the 
leaves of the sugar beet, potash and phosphoric acid reg- 
ularly and rapidly increase in relation to the other ingre- 
dients from without inward, while lime and magnesia as 
rapidly diminish in the same direction. The per cent of 
the other ingredients, viz., soda, chlorine, oxide of iron, 
sulphuric acid, and silica, remains nearly invariable 
throughout. 

Another illustration is furnished by the following anal- 
yses of the ashes of the various parts of the horse-chestnut 
tree, made by Wolff, {Aclcerbaii, 2. Aiif.^ 134) : 



THE ASH OF PLANTS. 159 

Bark. Wood. Leaf-stems. Leaves. Flmoer-stems. Calyx. 

Potash 12.1 25.7 46.2 27.9 63.6 61.7 

Lime 76.8 42.9 21.7 29.3 9.3 12.3 

Magnesia 1.7 5.0 3.0 2.6 1.3 5.9 

Sulphuric acid trace trace 3.8 9.1 3.5 trace 

Phosphoric acid 6.0 19.2 14.8 22.4 17.1 16.6 

Silica 1.1 2.6 1.0 4.9 0.7 1.7 

Chlorine 2.8 6.1 12.2 5.1 4.7 2.4 

Bipe Fruit. 

Stamens. Petals. Green Fruit. Kernel. Gh^een Brown 

SMI. SheU. 

Potash 60.7 61.2 58.7 61.7 75.9 54.6 

Lime., 13.8 13.6 9.8 11.5 8.6 16.4 

Magnesia 3.1 3.8 2.4 0.6 1.1 2.4 

Sulphuric acid trace trace 3.7 1.7 1.0 3.6 

Phosphoric acid ....19.5 17.0 20.8 22.8 5.3 18.6 

Silica 0.7 1.5 0.9 0.2 0.6 0.8 

Chlorine 2.8 3.8 4.8 2.0 7.6 5.2 

4 1 Similar hinds of plants.^ and especially the same 
parts of similar plants .^ exhibit a close general agreement 
in the composition of their ashes / while plants vnhich are 
unliJce in their botanical characters are also unlike in the 
proportions of their fixed ingredients. 

The three plants, wheat, rye, and maize, belong, botanical- 
ly speaking, to the same natural order, graminem^ and the 
ripe kernels yield ashes almost identical in composition. 
Barley and the oat are also graminaceous plants, and their 
seeds should give ashes of similar composition. That such 
is not the case is chiefly due to the fact, that, unlike the 
wheat, rye, and maize-kernel, the grains of barley and 
oats are closely invested with a husk, which forms a part 
of the kernel as ordinarily seen. This husk yields an ash 
which is rich in silica, and we can only properly compare 
barley and oats with wheat and rye, when the former are 
hulled, or the ash of the hulls is taken out of the account. 
There are varieties of both oats and barley, whose husks 
separate from the kernel — ^the so-called naked or skinless 
oats and naked or skinless barley — and the ashes of these 
grains agree quite nearly in composition with those of wheat, 
rye, and maize, as may be seen from the following table : 



160 HOW CKOPS GROW. 

Wheat. Eye. Maize. Skinless Skinless 

Average Average Average oats. barley, 

of of of Analysis Analysis 

seventy-nine ticenty-one seven by Fr. by Fr. 

a7ialyses. analyses. analyses. Schulze. SdmLze. 

Potash 31.3 26.8 27.7 33.4 35.9 

Soda 3.2 4.3 4.0 1.0 

Magnesia 12.3 11.6 15.0 11.8 13.7 

Lime 3.2 3.9 1.9 3.6 2.9 

Oxide of Iron... 0.7 0.8 1.0 0.8 0.7 

Phosphoric acid. 40. 1 45.6 47.1 46.9 45.0 

Sulphuric acid. . . 1.2 1.9 1.7 

Silica 1.9 2.6 2.1 2.4 0.7 

Chlorine 0.2 0.7 0.1 

By reference to the table, (p. 152,) it will be observed 
that the pea and bean kernel, together with the allied vetch 
and lentil, (p. 3T9,)also nearly agree in ash-composition.* 

So, too, the ashes of the root-crops, turnips, carrots, and 
beets, exhibit a general similarity of composition, as may 
be seen in the table, (p. 154-5). 

The seeds of the oil-bearing plants likewise constitute a 
group whose members agree in this respect, p. 379. 

5. The ash of the same species of plant is more or less 
variable in composition, according to circumstances. 

The conditions that have already been noticed as in- 
fluencing the j^roportion of ash are in general the same 
that affect its quality. Of these we may specially notice : 

a. The stage of growth of the plant. 

h. The vigor of its development. 

c. The variety of the plant or the relative development 
of its parts, and 

d. The soil or the supplies of food. 

a. The stage of growth. The facts that the different 
parts of a plant yield ashes of different composition, and 
that the difterent stages of growth are marked by the 
development of new organs or the unequal expansion of 
those already formed, are sufiicient to sustain the point 
now in question, and render it needless to cite analytical 
evidence. In a subsequent chapter, wherein we shall at- 
tempt to trace some of the various steps in the progressive 



THE ASH OF PLAOTTS. , IGl 

development of the plant, numerous illustrations will be 
adduced, (p. 214.) 

h. Yig or of development. Ar Qndit, (Die Saferpflanze, 
p. 18,) selected from an oat-field a number of plants in 
blossom, and divided them into three parcels — 1, composed 
of very vigorous plants ; 2, of medium ; and, 3, of very- 
weak plants. He analyzed the ashes of each parcel, with 
results as below : 

12 3 

Silica 37.0 39.9 42.0 

Sulphuric acid 4.S 4.1 5.0 

Phosphoric acid 8.2 8.5 8.8 

Clilorine 6.7 5.8 4.7 

Oxideoflron 0.4 0.5 1.0 

Lime 6.1 5.4 5.1 

Magnesia, Potash & Soda. 45.3 34.3 30.4 

Here we notice that the ash of the w^eak plants contains 
15 per cent less of alkalies, and 15 per cent more of silica, 
than that of the vigorous ones, while the proportion of the 
other ingredients is not greatly difierent. 

Zoeller, (Lieblg'^s Ernahrung der Vegetabilieny p. 340,) 
examined the ash of two specimens of clover which grew 
on the same soil and under similar circumstances, save 
that one, from being shaded by a tree, was less fully devel- 
oped than the other. 

Six weeks after the sowing of the seed, the clover was 

cut, and gave the following results on partial analysis : 

Sliaded clover. Uiishaded dover. 

Alkalies 54.9 • 36.2 

Lime...., 14.2 22.8 

Silica 5.5 12.4 

c. The variety of the plant or the relative development 
of its parts must obviously influence the composition of 
the ash taken as a whole, since the parts themselves are 
unlike in composition. 

Herapath, ( Qu. Jour. Chem. Soc, H, p. 20,) analyzed 
the ashes of the tubers of five varieties of potatoes, raised 
on the same soil and under precisely similar circumstances. 
His results as follows : 



162 HOW CEOPS GEOW. 

White Prince's Axbridge Magine. Forty-fold. 

Apple. Beauty. Kidney. 

Potash 69.7 65.2 70.6 70.0 62.1 

Chloride of Sodium. 2.5 

Lime 3.0 1.8 5.0 5.0 3.3 

Magnesia 6.5 5.5 5.0 2.1 3.5 

Phosphoric acid.... 17. 2 20.8 14.9 14.4 20.7 

Sulphuric acid 3.6 6.0 4.3 7.5 7.9 

Silica 0.2 

d. The soil., or the supplies of food, manures included., 
have the greatest influence in varying the proportions of 
the ash-ingredients of the plant. It is to a considerable 
degree the character of the soil which determines the 
vigor of the plant and the relative development of its 
parts. This condition then, to a certain extent, includes 
those already noticed. 

It is well known that oats have a great range of weight 
per bushel, being nearly twice as heavy when grown on 
rich land, as when gathered from a sandy, inferior soiL 
According to the agricultural statistics of Scotland, for the 
year 1857, {Trans. Highland and Ag. Soc, 1857 — 9,p, 
213,) the bushel of oats produced in some districts weigh- 
ed 44 pounds per bushel, while in other districts it was as 
low as 35 pounds, and in one instance but 24 pounds per 
bushel. Light oats have a thick and bulky husk, and an 
ash-analysis gives a result quite unlike that of good oats. 
Herapath, {Jour. Roy. Ag. of Eng., XI.,/>. 107,) has pub- 
lished analyses of light oats from sandy soil, the yield be- 
ing six bushels per acre, and of heavy oats from the same 
soil, after " warping,"* where the produce was 64 bushels 
per acre. Some of his results, per cent, are as follows : 

Light oats. HeavTj oats. 

Potash 9.8 13.1 

Soda 4.6 7.2 

Lime 6.8 4.3 

Phosphoric acid... 9.7 17.6 

Silica 56.5 45.6 

Wolif, {Jour, far FraJct. Chem.,52,p. 103,) has anal- 



* Thickly covering with sediment from muddy tide-water. 



THE ASH OF PLANTS. 163 

ysed the ashes of several plants, cultivated in a poor soil, 
with the addition of various mineral fertilizers. The in- 
fluence of the added substances on the composition of the 
plant is very striking. The following figures comprise 
his results on the ash of buckwheat straw, which grew on 
the unmanured soil, and on the same, after application of 
the substances specified below : 

1 2 3 4 5 6 

Unma- CMoride Nitrate Carbonate Sulphate Carbonate 

of of of of of 

mired, sodium, 2^ot(ish. potasJi, magnes-ia. limA. 

Potash 31.7 21. U 39.6 40.5 28.2 23.9 

Chloride of potassium. 7.4 26.9 0.8 3.1 6.9 9.7 

Chloride of sodium.... 4.6 3.0 3.2 3.8 3.4 1.7 

Lime 15.7 14.0 12.8 11.6 14.1 18.6 

Magnesia 1.7 1.9 3.3 1.4 4.7 4.2 

Sulphuric acid 4.7 2.8 2.7 4.3 7.1 3.5 

Phosphoric acid 10.3 9.5 6.5 8.9 10.9 10.0 

Carbonic acid 20.4 16.1 27.1 22.2 20.0 23.2 

Silica 3.6 4.2 4.2 4.2 4.8 5.2 

100.0 100.0 100.0 100.0 100.0 100.0 

It is seen from these figures that all the applications 
employed in this experiment exerted a manifest influence, 
and, in general, the substance added, or at least one of its 
ingredients, is found in the plant in increased quantity. 

In 2, chlorine, but not sodium ; in 3 and 4, j^otash ; in 
5, sulphuric acid and magnesia, and in 6, lime, are present 
in larger proportion than in the ash from the unmanured 
soil. 

6* What is the Normal Composition of the Ash of a 
Plant f It is evident from the fores^oino^ facts and consid- 
erations that to pronounce upon the normal composition 
of the ash of a plant, or, in other words, to ascertain what 
ash-ingredients and what proportions of them are proper 
to any species of plant or to any of its parts, is a matter 
of much difficulty and uncertainty. 

The best that can be done is to adoj)t the average of a 
great number of trustworthy analyses as the approximate 
expression of ash-composition. From such data, however, 
v/e are still unable to decide what are the absolutely es- 



164 HOW CEOPS GEOW. 

sential, and what are really accidental ingredients, or what 
amount of any given ingredient is essential, and to what 
extent it is accidental. Wolff, who appears to have first 
suggested that a part of the ash of plants may be acci- 
dental, endeavored to approach a solution of this question, 
by comparing together the ashes of samples of the same 
plant, cultivated under the same circumstances in all re- 
spects, save that they were supjilied with unequal quantities 
of readily available ash-ingredients. The analyses of the 
ashes of buckwheat-stems, just quoted, belong to this in- 
vestigation. Wolff showed that, by assuming the presence 
in each specimen of buckwheat-straw of a certain excess 
of certain ingredients, and deducting the same from the 
total ash, the residuary ingredients closely approximated 
in their proportions to those observed in the crop which 
grew in an unmanured soil. The analyses just quoted, 
(p. 163,) are here "corrected" in this manner, by the sub- 
traction of a certain per cent of those ingredients which 
in each case were furnished to the plant by the fertilizer 
applied to it. The numbers of the analyses correspond 
with those on the previous page. 

13 3 4 5 6 

HOp.c. 20^;. c. 25/;. c. 8.5;;. c. IG.Gp.c. 

Chloride Carbonate Carbonate Sulphate Carbonates 

After deduction of of of of of lime and 

of Nothing, potassium, potash, potash, magnesia, magnesia. 

Potash 31.7 27.0 33.5 33.5 30.6 28.0 

Chloride of potassium. 7.4 9.1 1.0 3.9 7.4 11.3 

Chloride of sodium. .. . 4.6 3.8 4.0 4.7 3.7 1.9 

Lime 15.7 17.3 16.0 14.5 15.3 14.6 

Magnesia 1.7 2.4 4.1 1.7 2.3 2.9 

Sulphuric acid 4.7 3.5 3.4 5.4 2.1 4.1 

Phosphoric acid 10.3 ' 11.7 8.1 11.2 11.8 11.7 

Carbonic acid 20.4 20.1 25.9 19.8 21.6 19.3 

Silica 3.6 5.2 5.2 5.3 5.2 6.1 

100.0 100.0 100.0 100.0 100 100.0 

The correspondence in the above analyses thus " cor- 
rected," already tolerably close, might, as Wolff remarks, 
(loc. cit.) be made much more exact by a further correc- 
tion, in which the quantities of the two most variable in- 



THE ASH OP PLANTS. 165 

gredients, viz. chlorine and sulpliuric acid, should "be re- 
duced to uniformity, and the analyses then be recalculated 
to per cent. 

In the first place, however, we are not warranted in 
assuming that the " excess " of chloride of potassium, car- 
bonate of potash, etc., deducted in the above analyses 
respectively, was all accidental and unnecessary to the 
plant, for, under the influence of an increased amount of a 
nutritive ingredient, the plant may not only mechanically 
contain more, but may chemically employ more in the 
vegetative processes. It is well proved that vegetation 
grown under the influence of large supplies of nitrogenous 
manures, contains an increased proportion of nitrogen in 
the truly assimilated state of albumin, gluten, etc. The 
same may be equally true of the various ash-ingredients. 

Again, in the second j^lace, we cannot say that in any 
instance the minimum quantity of any ingredient neces- 
sary to the vegetative act is present, and no more. 

It must be remarked that these great variations are only 
seen when we compare together plants produced on poor 
soils, i. e. on those which are relatively deficient in some 
one or several ingredients. If a fertile soil had been em- 
ployed to support the buckwheat plants in these trials, we 
should doubtless have had a very diflerent result. 

In 1859, Metzdorf, ( Wilda's Gentralhlatt, 1862, 2, p. 
367,) analysed the ashes of eight samples of the red-onion 
potato, grown on the same field in Silesia, but difierently 
manured. 

Without copying the analyses, we may state some of 
the most striking results. The extreme range of variation 
in potash was 5|- per cent. The ash containing the high- 
est percentage of potash was not, however, obtained from 
potatoes that had been manured with 50 pounds of this 
substance, but from a parcel to which had been applied a 
poudrette containing less than 3 pomids of potash for the 
quantity used. 



166 HOW CKOPS GROW. 

The unmanured potatoes were relatively the richest in 
lime, phosphoric acid, and sulphuric acid, although several 
parcels were copiously treated with manures containing 
considerable quantities of these substances. These facts 
are of great interest in reference to the theory of the action 
of manures. 

7. To what Extent is each Ash-ingredient Essential^ 
and how far may it he Accidental? Before the art of 
chemical analysis had arrived at much perfection, it was 
believed by many men of science, that the ashes of the 
l^lant were either unessential to growth, or else were the 
products of growth — were generated by the plant. 

Since the substances found in ashes are universally dis- 
tributed over the earth's surface, and are invariably j)res- 
ent in all soils, it is not possible by analysis of the ash of 
plants growing under natural conditions, to decide whether 
any or several of their ingredients are indispensable to veg- 
etative life. For this purpose it is necessary to institute 
experimental inquiries, and these have been prosecuted 
with great pains-taking, though not Avith results that are in 
all respects satisfactory. 

Experiments in Artificial Soils. — The Prince Salm- 
Horstmar, of Germany, has been a most laborious student 
of this question. His plan of experiment was the follow- 
ing : the seeds of a plant were sown in a soil-like medium, 
(sugar-charcoal, pulverized quartz, purified sand,) which 
was as thoroughly as j)ossible freed from the substance 
whose special influence on growth was the subject of study. 
All other substances presumably necessaiy, and all the 
usual external conditions of growth, (light, warmth, 
moisture, etc.,) were supplied. 

The results of 195 trials thus made with oats, wheat, 
barley, and colza, subjected to the influence of a great 
variety of artificial mixtures, have been described, the 
most important of which will shortly be given. 



THE ASH OF PLANTS. 



1G7 



Experiments in Solutions.— Water-Culture.— Sachs, 

"W. Knop, Stohmann, I^obbe, Siegert, and others have 
likewise studied this subject. Their method was like that 
of Prince Salm-Horstmar, except that the plants were 
made to germinate and grow independently of any -soil ; 
and, throughout the experiment, had their roots immersed 
in water, containing in solution or suspension the sub- 
stances whose action was to be observed. 

Water- Culture has recently contributed so much to our 
knowledge of the conditions of vegetable growth, that 
some account of the mode of conducting it may be proper- 
ly given in this place. Cause a 
number of seeds of the plant it is 
desired to experiment upon to ger- 
minate in moist cotton or coarse sand, 
and when the roots have become an 
inch or two in length, select the 
strongest seedlings, and support them, 
so that the roots shall be immersed in 
water, while the seeds themselves shall 
be just above the surface of the liquid. 

For this purpose, in case of a single 
maize plant, for example, provide a 
quart cylinder or bottle, with a wide 
mouth, to which a cork is fitted, as in 
Fig. 22. Cut a vertical notch in the 
cork to its center, and fix therein the 
stem of the seedling by packing with 
cotton. The cork thus serves as a 
support of the plant. Fill the jar 
with pure water to such a height 
that when the cork is brought to its 
place, the seed, /S', shall be a little 
above the liquid. If the endosperm 
or cotyledons dip into the water, they will speedily 
mould and rot; they require, however, to be kept in 




Fiff. 23. 



168 HOW CKOPS GKOW. 

a moist atmosphere. Thus arranged, suitable warmth, 
ventilation, and illumination, alone are requisite to con- 
tinue the growth until the nutriment of the seed is nearly- 
exhausted. As regards illumination, this should be as full 
as possible, for the foliage ; but the roots should be pro- 
tected from it, by enclosing the vessel in a shield of black 
paper, as, otherwise, minute parasitic algae would in time 
develop upon the roots, and disturb their functions. For 
the first days of growth, pure distilled water may advan- 
tageously surround the roots, but when the first green leaf 
appears, they should be placed in the solution whose nu- 
tritive power is to be tested. The temperature should be 
properly proportioned to the light, in imitation of what is 
observed in the skillful management of conservatory or 
house-plants. 

The experimenter should first learn how to produce 
large and well-developed plants, by aid of an appropriate 
liqiiid, before attempting the investigation of other prob- 
lems. For this purpose, a solution or mixture must be 
prepared, containing in proper proportions all that the 
plant requires, save what it can derive from the atmos- 
phere. The recent experience of ISTobbe & Siegert, Wolif, 
and others, supplies valuable information on this point. 
Prof Wolff has obtained striking results with a variety of 
plants in using a solution made essentially as follows : 

Place 20 grams, (300 grains,) of the fine powder of well- 
burned bones with a half pint of water in a large glass 
flask, heat to boiling, and add nitric acid cautiously in 
quantity just sufficient to dissolve the bone-ash. In order 
to remove any injurious excess of nitric acid, pour into the 
hot liquid, solution of carbonate of potash until a sliglit 
permanent turbidity is produced; then add 11 grams, (180 
grains,) of nitrate of potash, 7 grams, (107 grains,) of 
crystallized sulphate of magnesia, and 3 grams, (60 grains,) 
of chloride of potassium, with water enough to make the 
solution up to the bulk of one liter, (or quart.) Mix 30 



THE ASH OF PLANTS. 169 

cubic ceht., (one fluid ounce,) of this liquid with a liter, 
(or quart,) of water and a single drop of strong solution 
of sulphate of iron, and employ this diluted solution to 
feed the plant. 

Wolff's solution, thus prepared, contained in 1000 parts 
as follows, exclusive of iron : 

Phosphoric acid - - 8.234 
Lime - - - - 10.370 
Potash - - - - 9.123 
Magnesia - - - - 1.403 
Sulphuric acid - - - 2.254 
Chlorine .... 0.885 
Mtricacid - - - 29.703 

Solid Matters - - - - • 61.972 
Water - - - - - 938.028 



1000. 

This solution was diluted to a liquid containing but one 
part of solid matters to 1000 or 2000 parts of water. 

The solution should be changed every week, and as the 
plants acquire greater size, their roots should be trans- 
ferred to a larger vessel, filled with solution of the same 
strength. 

It is important that the water which escapes from the 
jar by evaporation and by transpiration through the plant, 
should be daily or oftener replaced, by filling it with pure 
water up to the original level. The solution, whose prep- 
aration has been described, may be turbid from the sepa- 
ration of a little white sulphate of lime before the last dilu- 
tion, as well as from the precipitation of phosphate of iron 
on adding sulphate of iron. The former deposit may be 
dissolved, though this is not needful ; the latter will not 
dissolve, and should be occasionally put into suspension by 
stirring the liquid. When the plant is half grown, further 
addition of iron is unnecessary. 

In this manner, and with this solution, Wolff produced 
8 



170 HOW CKOPS GROW. 

a maize plant, five and three quarters feet high, and equal 
in every respect, as regards size, to plants from similar 
seed, cultivated in the field. The ears were not, however, 
fully developed when the experiment was interrupted by 
the plant becoming unhealthy. 

With the oat his success was better. Four plants were 
brought to maturity, having 46 stems and 1535 well-devel- 
oped seeds. ( Vs. St., VIII, 190-215.) 

In similar experiments, Nobbe obtained buckwheat 
plants, six to seven feet high, bearing three hundred plump 
and perfect seeds, and barley stools with twenty grain- 
bearing stalks. ( Vs. St., VII, 72.) 

In water-culture, the composition of the solution is suf- 
fering continual alteration, from the fact that the plant 
makes, to a certain extent, a selection of the matters pre- 
sented to it, and does not necessarily absorb them in the 
proportions in which they originally existed. In this way, 
disturbances arise which impede or become fatal to growth. 
In the early experiments of Sachs and Knop, in 1860, they 
frequently observed that their solutions suddenly acquired 
the odor of sulphydric acid, and black sulphide of iron 
formed upon the roots, in consequence of which they were 
shortly destroyed. This reduction of a sulphate to a sul- 
phide takes place only in an alkaline liquid, and Stohmann 
was the first to notice that an acid liquid might be made 
alkaline by the action of living roots. The plant, in fact, 
has the power to decompose salts, and by appropriat- 
ing the acids more abundantly than the bases, the latter 
accumulate in the solution in the free state, or as carbon- 
ates with alkaline properties. 

To prevent the reduction of sulphates, the solution must 
be kept slightly acid, best by addition of a very little free 
nitric acid, and if the roots blacken, they must be washed 
with a dilute acid, and, after rinsing with water, must be 
transferred to a fresh solution. 

On the other hand, Ktihn has shown that when chloride 



THE ASH OF PLANTS. ITl 

of ammonium is employed to supply maize with nitrogen, 
this salt is decomposed, its ammonia assimilated, and its 
chlorine, which the plant cannot use, accumulates in the 
solution in the form of chlorhydric acid, to such an extent 
as to prove fatal to the plant, {Senneberg^s Journal, 1864, 
pp. 116 and 135.) Such disturbances are avoided by 
employing large volumes of solution, and by frequently 
renewing them. 

The concentration of the solution of is by no means a 
matter of indifference. While certain aquatic plants, as 
sea- weeds, are naturally adapted to strong saline solutions, 
agricultural land-plants rarely succeed well in water-cul- 
ture, when the liquid contains more than ^ Ij^^^ of solid mat- 
ters, and will thrive in considerably weaker solutions. 

Simple well-water is often rich enough in plant-food to 
nourish vegetation perfectly, provided it be renewed suf- 
ficiently often. Sachs' earliest experiments were made with 
well-water. 

Birner and Lucanus, in 1864, '( Vs. St., YIII, 154,) raised 
oat-plants in well-water, which in respect to entire weight 
were more than half as heavy as plants that grew simul- 
taneously in garden soil, and, as regards seed-production, 
fully equalled the latter. The well-water employed, con- 
tained in 100.000 parts : 

Potash 2.10 

Lime 15.10 

Magnesia 1.50 

Phosphoric acid - - , - - 0.16 
Sulphuric acid - - / - - 7.50 
Mtric acid - - - - - 6.00 
Silica, Chlorine, Oxide/of iron - - traces 



Solid Matters - - - / - - - - 32.36 

Water 99,967.64 

100,000 

Nobbe, ( Vs. St., Vin, 337,) found that in a solution con- 
taining but ^ Ijoooo of solid matters, which was continually 



172 HOW CEOPS GEOW. 

renewed^ barley made no progress beyond germination, and 
a buckwheat plant, which at first grew rapidly, was soon 
arrested in its development, and yielded but a few ripe 
seeds, and but 1.746 grm. of total dry matter. 

"While water-culture does not provide all the normal 
conditions of growth — the soil having important func- 
tions that cannot be enacted by any liquid medium — it 
is a method of producing highly-developed plants, under 
circumstances which admit of accurate control and great 
variety of alteration, and is, therefore, of the utmost value 
in vegetable physiology. It has taught important facts 
which no other means of study could reveal, and promises 
to enrich our knowledge in a still more eminent degree. 

Potash, Lime, Magnesia, Pliosphoric Acid, and Sul- 
phuric Acid, are ahsolutely necessary for the life of 
Agricultural Plants, as is demonstrated by all the experi- 
ments hitherto made for studying their influence. 

It is not needful to recount here the evidence to this 
effect that is furnished by the investigations of Salm- 
Horstmar, Sachs, Knop, and others. (See, especially, 
Birner & Lucanus, Vs. St., VHI, 128-161.) 

Is Soda Essential for Agricultural Plants? This 
question has occasioned much discussion. A glance at 
the table of ash-analyses, (pp. 150-56,) will show that the 
range of variation is very great as regards this alkali. 
Among the older analysts, Bichon found in the ash of 
the pea 13, in that of the bean 19, in that of rye 19, in that 
of wheat 27 per cent of soda. Herapath found 15 per cent 
of this substance in wheat -ash, and 20 per cent in ash of 
rye. Brewer fonnu 13 per cent in the ash of maize. In a 
few other analyses of the grains, we find similar high per- 
centages. In most of the analyses, however, soda is pres- 
ent in much smaller quantity. The average in the ashes 
of the grains is less than 3 per cent, and in not a few of 
the analyses it is entirely wanting. 



THE ASH OF PLANTS. 173 

In the older analyses of otlier classes of agricultural 
plants, especially in root crops, similarly great variations 
occur. 

Some uncertainty exists as to these older data, for the 
reason that the estimation of soda by the processes custom- 
arily employed is liable to great inaccuracy, especially 
with the inexperienced analyst. On the one hand, it is 
not easy, (or has not been easy until lately,) to detect, 
much less to estimate, minute traces of soda, when mixed 
with much potash ; while on the other hand, soda, if pres- 
ent to the extent of a per cent or more, is very liable to 
be estimated too high. It has therefore been doubted if 
these high percentages in the ash of grains are correct. 

Again, furthermore, the processes formerly employed for 
preparing the ash of plants for analysis were such as, by 
too elevated and prolonged heating, might easily occasion 
a partial or total expulsion of soda from a material which 
l^roperly should contain it, and we may hence be in doubt 
whether the older analyses, in which soda is not mention- 
ed, a^re to be altogether depended upon. 

The later analyses, especially those by Bibra, Zoeller, 
Arendt, Bretschneider, Ritthausen, and others, who have 
employed well-selected and carefully-cleaned materials for 
their investigations, and who have been aware of all the 
various sources of error incident to such analyses, must 
therefore be appealed to in this discussion. From these 
recent analyses we are led to precisely the same conclusions 
as were warranted by the older investigations. Here fol- 
lows a statement of the range of percentages of soda in the 
ash of several field crops, according to the newest analyses : 
Ash of Wheat kernel, none, Bibra, to S^lo Bibra. 

" " Potato tuber, none, | g'g^^^^[^Ji|.^ " 4o|o WolflF. 

" "Barley kernel i ^Ijo Ser " ^"^^ 1 VeUmann. 

( <i|o zoeller, ^„|^ Zoeller. 

« "-^no-orhPPf j4.7o|o Ritthausen, " 29.8o|o Ritthausen. 

bugai oeei, "j 5. 7o|o Bretschneider" 16. 6o|o Bretschneider. 

" " Turnip root, 7.7o|o Anderson, " 17.1»|o Anderson. 



174 HOW CROPS GROW. 

Although, as just indicated, soda has been found want- 
ing in the wheat kernel and in potato tubers, in some in- 
stances, it is not certain that it was absent from other 
parts of the same plants, nor has it been proved, so far as 
we know, that soda is wanting in any entire plant which 
has grown on a natural soil. 

Weinhold found in the ash of the stem and leaves of the 
common live-for-ever, {Sediim telepMum^ no trace of soda 
detectable by ordinary means ; while in the ash of the 
roots of the same plant, there occurred 1.8 per cent of this 
substance. ( Vs. St., lY, p. 190.) 

It is possible, then, that, in the above instances, soda 
really existed in the plants, though not in those parts 
which were subjected to analysis. It should be added 
that in ordinary analyses, where soda is stated to be ab- 
sent, it is simply im^Dlied that it is present in unweighable 
quantity,* if at all, while in reality a minute amount may 
be present in all such cases.f 

The grand result of all the analytical investigations 
hitherto made, with regard to cultivated agricultural 
plants, then, is that soda is an extremely variable ingre- 
dient of the ash of plants^ and though generally present 
in some proportion, and often in large proportion, has 
heeti observed to he absent in weighable qxiantity in the 
seeds of grains and in the tubers of potatoes. 

Salm-Horstraar, Stohmann, Knop, and N'obbe & Sie- 
gert, have contributed certain synthetical data that bear 
on the question before us. 

The investigations of Salm-Horstmar were made witli 
the greatest nicety, and especial attention was bestowed * 
on the influence of very minute quantities of the various 



* TJiiweighable quantities are designated as " trace" or "traces." 
t The newly discovered methods of spectral analysis, by which -_^-^--__ 
of a grain of soda may he detected, have demonstrated that this element is so 
universally distributed that it is next to impossible to find or make anything that 
is free from it. 



THE ASH OF PLANTS. 175 

substances employed. He gives as the result of numerous 
experiments, that for wheat, oats, and barley, in the early 
vegetative stages of growth^ soda^ while advantageous^ 
is not essential, hut that for the perfection of fruit an ap- 
preciahle though minute quantity of this substance is in- 
dispensable. ( Yersuche und Result ate uber die Nahrung 
der Fflanzen, pp. 12, 27, 29, 36.) 

Stohmann's single experiment led to the similar conclu- 
sion, that maize may dispense with soda in the earlier 
stages of its growth, but requires it for a full development. 
{Hennebergh Jour, far Landwirthschaft, 1862, p. 25.) 

Knop, on the other hand, succeeded in bringing the 
maize plant to full perfection of parts, if not of size, in a 
solution which was intended and asserted to contain no 
soda. ( Vs. St., in, p. 301.) Nobbe & Siegert came to 
the same results in similar trials with buckwheat. ( Vs. 
St., lY, p. 339.) 

The experiments of Knop, and of N"obbe Sd Siegert, 
while they prove that much soda is not needful to maize 
and buckwheat, do not, however, satisfactorily demon- 
strate that a trace of soda is not necessary, because the 
solutions in which the roots of the plants were immersed 
stood for months in glass vessels, and could scarcely 
fail to dissolve some soda from the glass. Again, 
slight impurity of the substances which were employed in 
making the solution could scarcely be avoided without 
extraordinary precautions, and, finally, the seeds of these 
plants might originally have contained enough soda to 
supply this substance to the plants in appreciable quantity. 

To sum up, it appears from all the facts before us : 

1. That soda is never totally absent from plants, but 
that, 

2. If indispensable, but a minute amount of it is re- 
quisite. 

3. That the foliage and succulent portions of the plant 



176 HOW CK0PS GEOW. 

may include a considerable araoimt of soda that is not nec- 
essary to the plant, that is, in other words, accidental.* 

Can Soda replace Potash ? — The close similarity of pot- 
ash and soda, and the variable quantities in which the 
latter especially is met with in plants, has led to the as- 
sumption that one of these alkalies can take the place of 
the other. 

Salm-Horstmar, and, more recently, Knop & Schreber, 
have demonstrated that soda cannot entirely take the place 
of potash — ill other words, potash is indispensable to plant 
life. Cameron concludes from a series of experiments, 
which it is unnecessary to describe, that soda G2in partially 
replace potash. A partial replacement of this kind would 
appear to be indicated by many facts. 

Thus, Herapath has made two analyses of asparagus, 
one of the wild, the other of the cultivated plant, both 
gathered in flower. The former was rich in soda, the lat- 
ter almost destitute of this substance, but contained cor- 
respondingly more potash. Two analyses of the ash of 
the beet, one by Wolff, (1.,) the other by Way, (2.,) ex- 
hibit similar differences : 

Asparagus. Field Beet 

Wild. Cultivated. 1. 3. 

Potash 18.8 50.5 57.0 25,1 

Soda 16.2 trace 7.3 34.1 

Lime 28.1 21.3 5.8 2.2 

Magnesia 1.5 4.0 2.1 

Chlorine 16.5 8.3 4.9 34.8 

Sulphuric acid 9.2 4.5 3.5 3.6 

Phosphoric acid 12.8 12.4 12.9 1.9 

Silica 1.0 3.7 3.7 1.7 

These results go to show — it being assumed that only a 
very minute amount of soda, if any, is absolutely neces- 
sary to plant-life — that the soda which appears to replace 
potash is accidental, and that the replaced potash is acci- 



* Soda appears to be essential to animal life : since all the food of animals is 
derived, indirectly at least, from the vegetable kingdom, it is a wise provision 
that soda is contained in, if it be not indispensable to plants. 



THE ASH OF PLANTS. 177 

dental also, or in excess above what is really needed by 
the plant, and leaves us to infer that the quantity of 
these bodies absorbed, depends to some extent on the com- 
position of the soil, and is to the same degree independent 
of the wants of vegetation. 

Alkalies in Strand and Marine Plants,— The above 
conclusions cannot as yet be accepted in case of plants 
which grow only near or in salt water. Asparagus, the 
beet and carrot, though native to saline shores, are easily 
capable of inland cultivation, and indeed grow wild in 
total or comparative absence of soda-compounds.* 

The common saltworts, Salsola, and the samphire, Sali- 
cornia, are plants, which, unlike those just mentioned, 
never stray inland. Gobel, who has analyzed these plants 
as occurring on the Caspian steppes, found in the soluble 
part of the ash of the Salsola hrachlata, 4.8 per cent of 
potash, and 30.3 per cent of soda, and in the Salicornia 
herhacea, 2.6 per cent of potash and 36.4 per cent of soda; 
the soda constituting in the first instance no less than ^[^^ 
and in the latter ^l^^ of the entire weight, not of the ash, 
but of the air-dry plant. Potash is never absent in these 
forms of vegetation. {Agricultur-Chemie^ Zte Auf.^ p. 66.) 

According to Cadet, {Liehig^s JSrndhrung der Veg., p. 
100,) the seeds of fhe Salsola kali, sown in common garden 
soil, gave a plant which contained both soda and potash ; 
from the seeds of this, sown also in garden soil, grew plants 
in which only potash-salts with traces of soda could be 
found. 

Another class of plants — the sea-weeds, (algae,) — derive 
their nutriment exclusively from the sea- water in which 
they are immersed. Though the quantity of potash in sea- 
water is but ^ I30 that of the soda, it is yet a fact, as shown 
by the analyses of Forchhammer, {Jour far Braht, Chem., 



* This is not, indeed, proved by analysis, in case of the carrot, hut is doubt- 
less true. 

8* 



178 HOW CEOPS GROW. 

36, p. 391,) and Anderson, {Trans. High, mid Ag. Soc, 
1855-7, p. 349,) that the ash of sea-weeds is, in general, 
as rich, or even richer, in potash than in soda. In 14 
analyses, by Forchhammer, the average amount of soda 
in the dry weed was 3.1 per cent; that of potash 2.5 per 
cent. In Anderson's results, the percentage of potash is 
invariably higher than that of soda.* 

Analogy with land-plants would lead to the inference 
that the soda of the sea-weeds is in a great degree acci- 
dental, although, necessarily, special investigations are re- 
quired to establish a point like this. 

Oxide of Iron is essential to plants. — ^It is abundant- 
ly proved that a minute quantity of oxide of iron, Fe^ O3, 
is essential to growth, though the agricultural plant 
may be perfect if provided with so little as to be 
discoverable in its ash only by sensitive tests. Accord- 
ing to Salm-Horstmar, t\\Q protoxide of iron is indispen- 
sable to the colza plant. ( Yersuche, etc., p. 35.) Knop as- 
serts that maize, which refuses to grow in entire absence 
of oxide of iron, flourishes when the phosphate of iron, 
which is exceedingly insoluble, is simply suspended in the 
solution that bathes its roots for the first four weeks only 
of the growth of the plant. ( Vs. St. Y, p. 101.) 

We find that the quantity of oxide of iron given in the 
analyses of the ashes of agricultural plants is small, being 
usually less than one per cent. 

Here, too, considerable variations are observed. In the 
analyses of the seeds of cereals, oxide of iron ranges from 
an unweighable trace to 2 and even 3°|„. In root crops it 
has been found as high as 5"! „. Kekule found in the ash 
of gluten from wheat 7.1° 1^ of oxide of iron. {Jdhres- 
hericht der Ghem., 1851, p. 715.) Schulz-Flceth found 
17.5" Iq in the ash of the albumin from the juice of the 



* Doubtless due to the fact that the material used by Anderson was freed by 
washing from adhering common salt. 



THE ASH OF PLANTS. 179 

potato tuber. The proportion of ash is, however, so small 
that in case of potato-albumin, the oxide of iron amounts 
to but 0.12 per cent of the dry substance. {Der Rationelle 
AcJcerhau, p. 82.) 

In the wood, and especially in the bark of trees, oxide 
of iron often exists to the extent of 5-10° |„. The largest 
percentages have been found in aquatic plants. In the ash 
of the duck-meat, {Lemna trisulca,) Liebig found 7.4° 1^. 
Gorup-Besanez found in the ash of the leaves of the Trapa 
natans 29.6° 1^, and in the ash of the fruit-envelope of the 
same plant 68.6°| „. {Ann. Gh. Ph., 118. p. 223.) 

Probably much of the iron of agricultural and land 
plants is accidental. In case of the Trapa natans, we 
cannot suppose all the oxide of iron to be essential, be- 
cause the larger share of it exists in the tissues as a brovrn 
powder, which may be extracted by acids, and has the ap- 
pearance of having accumulated there mechanically. 

Doubtless a portion of the oxide of iron encountered in 
analyses of agricultural vegetation has never once existed 
within the vegetable tissues, but comes from the soil w^hich 
adheres with great tenacity to all parts of plants. 

Oxide of Manganese, Mvl^ 0,, is unessential to Agri- 
cultural Plants*^ — This oxide is commonly less abundant 
than oxide of iron, and is often, if not usually, as good as 
wanting in agricultural plants. It generally accom'panies 
oxide of iron where the latter occurs in considerable quan- 
tity. Thus, in the ash of Trapa, it was found to the extent 
of 7.5-14.7° I Q. Sometimes it is found in much larger quan- 
tity than oxide of iron; e. g., C. Fresenius found 11.2° !„ 
of oxide of manganese in ash of leaves of the red beech, 
{Fagus sylvatica,) that contained but 1° !„ of oxide of iron. 
In the ash of oak leaves, ( Quercus rohur^ IN'eubauer found, 
of the former 6.6, of the latter but 1.2° |„. 

In ash of the wood of the larch, (Larix Miropoea,) 
Bottinger found 13.5° |, Mn3 O, and 4.2°] „ Fe, O3, and in 



180 HOW CEOPS GKOW. 

ash of wood of Pinus sylvestris 18.2° ]„ MHj O^, and 3.5" |„ 
Fe^ O3. In ash of the seed of colza, Nitzsch found 16.1" |g 
Mng O4, and 5.5 Fe^ O3. In case of land plants, these high 
percentages are accidental, and specimens of most of the 
plants just named have been analyzed, which were free 
from all but traces of oxide of manganese. 

Salm-Horstmar concluded from his experiments that 
oxide of manganese is indispensable to vegetation. Sachs, 
Knop, and most other experimenters in water-culture, make 
no mention of this substance in the mixtures, which in 
their hands have served for the more or less perfect devel- 
opment of a variety of agricultural plants. Birner & 
Lucanus have demonstrated that manganese is not needful 
to the oat-plant, and cannot take the place of iron. ( Vs. 

St., yiii, p. 43.) 

Is Chlorine indispensable to Crops?— What has 

been written of the occurrence of soda in plants ap- 
j)ears to apply in most respects equally well to chlo- 
rine. In nature, soda, or rather sodium, is generally 
associated with chlorine as common salt. It is most prob- 
ably in this form that the two substances usually enter 
the plant, and in the majority of cases, when one of them 
is present in large quantity, the other exists in correspond- 
ing quantity. Less commonly, the chlorine of plants is in 
combination with potassium exclusively. 

Chlorine is doubtless never absent from the perfect agri- 
cultural plant, as produced under natural conditions, though 
its quantity is liable to great variation, and is often very 
small — so small as to be overlooked, except by the careful 
analyst. In many analyses of grain, chlorine is not men- 
tioned. Its absence, in many cases, is due, without doubt, 
to the fact that chlorine is readily dissipated from the ash 
of substances rich in phosphoric, silicic, or sulphuric acids, 
on prolonged exposure to a high temperature. In the 
later analyses, in which the vegetable substance, instead 
of being at once burned to ashes, at a high red heat, is 



THE ASH OF PLA:NTS. 181 

first charred at a heat of low redness, and then leached 
Avith water, which dissolves the chlorides, and separates 
them from the unburned carbon and other matters, chlo- 
rine is invariably mentioned. In the tables of analyses, 
the averages of chlorine are undeniably too low. This is 
especially true of the grains. 

The average of chlorine in the 26 analyses of wheat by 
Way & Ogston, p. 150, is but 0.08" |„, it not being found at all 
in the ash of 21 samples. In Zoeller's later analyses, chlorine 
i& found in every instance, and averages 0.7" l^. Weber's 
analysis, as compared with the others, would indicate a 
considerable range of variability. Weber extracted the 
charred ash with water, and found 6" 1^ of chlorine, which 
is six times as much as is given in any other recorded anal- 
ysis of the wheat kernel. This result is in all probability 
erroneous. 

Like soda, chlorine is particularly abundant in the stems 
and leaves of those kinds of vegetation Avhich grow in soils 
or other media containing much common salt. It accom- 
panies soda in strand and marine plants, and, in general, 
the content of chlorine of any plant may be largely in- 
creased or diminished by supplying it to, or withholding 
it from the roots. 

As to the indispensableness of chlorine, we have some- 
what conflicting data. Salm-Horstmar concludes that a 
trace of it is needful to the wheat plant, though many of 
his experiments in reference to the importance of this ele- 
ment he himself regards as unsatisfactory. ISTobbe & 
Siegert, who have made an elaborate investigation on the 
nutritive relations of chlorine to buckwheat, were led to 
conclude that while the stems and foliage of this plant are 
able to attain a considerable development in the absence 
of chlorine, (the minute amount in the seed itself excepted,) 
presence of chlorine is essential to the perfection of the 
kernel. 

On the other hand, Knop excludes chlorine from the 



182 now CROPS GROW. 

list of necessary ingredients of maize, and from not yet 
fully described experiments doubts that it is necessary for 
buckwheat. 

Leydhecker, in a more recent investigation, has come to 
the same conclusions as Nobbe & Siegert, regarding the 
indispensableness of chlorine to the perfection of buck- 
wheat. ( Vs. St., VIII, 177.) 

From a series of experiments in water-culture, Birner 
& Lucanus, ( Vs. St., VIII, 160,) conclude that chlorine 
is not indispensable to the oat-plant, and has no specific 
effect on the production of its fruit. Chloride of potassium 
increased the weight of the crop, chloride of sodium gave 
a larger development of foliage and stem, chloride of mag- 
nesium was positively deleterious, under the conditiotis 
of their trials. 

Lucanus, ( Vs. St., VII, 363-71,) raised clover by wa- 
ter-culture without chlorine, the crop, (dry,) weighing in 
the most successful experiments 210 times as much as the 
seed. Addition of chlorine gave no better result. 

Nobbe, (notes to above paper,) has produced normally 
developed vetch and pea plants, but only in solutions con- 
taining chlorine. Knop, still more recently, (Lehrbuch 
der Agrlcultar-Chemie, p. 615,) gives his reasons for not 
crediting the justness of the conclusions of Nobbe & 
Siegert and Leydhecker. 

Until further more decisive results are reached, we are 
warranted in adopting, with regard to chlorine as related 
to agricultural plants, the following conclusions, viz.: 

1. Chlorine is never totally absent. 

2. If indispensable, but a minute amount is requisite in 
case of the cereals and clover. 

3. Buckwheat, vetches, and perhaps peas, require a not 
inconsiderable amount of chlorine for full development. 

4. Tlie foliage and succulent parts may include a con- 
siderable quantity of chlorine that is not indispensable to 
the life of the plant. 



THE ASH OF PLANTS. 183 

Necessity of Chlorine for Strand Plants.— A single 
observation of Wicgmann and Polstorf, {Prelsschrift,) 
indicates that Salsola kail requires chlorine, though 
whether it be united to potassium or sodium is indiffer- 
ent. These experimenters transplanted young salt-worts 
into a pot of garden soil which contained but traces of 
chlorine, and watered them with a weak solution of clilo- 
ride of potassium. The plants grew most luxuriantly, 
blossomed, and completely filled the pot. They were 
then put out into the earth, without receiving further ap- 
plications of chlorine-compounds, but the next year they 
became unhealthy, and perislied at the time of blossoming. 

Silica is not indispensable to Crops. — ^The numerous 
analyses wo now possess indicate that this substance is 
always present in the ash of all parts of agricultural 
plants, lohen they grow in natural soils. 

In the ash of the wood of trees, it usually ranges from 
1 to 3"|„, but is often found to the extent of 10-20" |„, 
or even 30" | „, especially in the pine. In leaves, it is usually 
more abundant than in stems. The ash of turnip-leaves 
contains 3-10"| „ ; of tobacco-leaves, 5-18" |„ ; of the oat, 11- 
58" |„. (Arendt, Norton.) In ash of lettuce, 20" |„ ; of beech 
leaves, 2G"| „ ; in those of oak, 31° 1^ have been observed. 
(Wicke, llennehergh Jour., 1862, p. 156.) 

The bark or cuticle of many plants contains an extraor- 
dinary amount of silica. The Cauto tree, of South America, 
(Hirtella sillcea,) is most remarkable in this respect. Its 
bark is very firm and harsh, and is difficult to cut, having the 
texture of soft sandstone. In Trinidad, the natives mix 
its ashes with clay in making pottery. The bark of the 
Cauto yields 34" |„ of ash, and of this 96" |„ is silica. (Wicke, 
Henneberg'' 8 Jour., 1862, p. 143.) 

Another plant, remarkable for its content of silica, is the 
bamboo. The ash of the rind contains 70" |„, and in the 
joints of the stem are often found concretions of silica, re- 
semblinir flint — the so-called TahasJiir. 



184 HOW CEOPS GEOW. 

The ash of the common scouring rush, [Equisetum hye- 
male^ has been found to contain 97.5° 1^ of silica. The 
straw of the cereal grains, and the stems and leaves of 
grasses, both belonging to the botanical family Graminece^ 
are specially characterized by a large content of silica, 
ranging from 40 to 70° l^,. The sedge and rush families 
likewise contain much of this substance. 

The position of silica in the plant would appear, from 
the percentages above quoted, to be, in general, at the sur- 
face. Although it is found in all parts of the plant, yet 
the cuticle is usually richest, and this is especially true in 
cases where the content of silica is large. Davy, in 1799, 
drew attention to the deposition of silica in the cuticle, and 
advanced the idea that it serves the plant an office of sup- 
port similar to that enacted in animals by the bones. 

In the ash of the pine, {Pinus sylvestris^ Wittstein has 
obtained results which indicate that the age of wood or 
bark greatly influences the content of silica. He found in 

Wood of a tree, 220 years old, 32.5''lr 
a » (i « 170 " " 24.1 
" " " " 135 " " 15.1, and in 

Bark " " " 220 " " 30.3 
a u u 170 " " 144 

In the ash of the straw of the oat, Arendt found the per- 
centage of silica to increase as the plant approached maturi- 
ty. So the leaves of forest trees, which in autumn are rich 
in silica, are nearly destitute of this substance in spring 
time. Silica accumulates then, in general, in the older and 
less active parts of the plant, whether these be external or 
internal, and is relatively deficient in the younger and 
really growing portions. 

This rule is not without exceptions. Thus, the chaff of 
wheat, rye, and oats, is richer in silica than any other part 
of these plants, and Bottinger found the seeds of the pine 
richer in silica than the wood. 

In numerous instances, silica is so deposited in or upon 



THE ASH OF PLAKTS. 185 

the cell-wall, that when the organic matters are destroyed 
by burning, or removed by solvents, the form of the cell 
is preserved in a silicious skeleton. This has long been 
known in case of the Equisetums and Deutzias. Here, the 
roughnesses of the stems or leaves which make these plants 
useful for scouring, are fully incrusted or interpenetrated 
by silica, and the ashes of the cuticle present the same ap- 
pearance under the microscope as the cuticle itself. 

Lately, Kindt, Wicke, and Mohl, have observed that the 
hairs of nettles, hemp, hops, and other rough-leaved plants, 
are highly silicious. 

The bark of the beech is coated with silica — ^hence the 
smooth and undecayed surface which its trunk presents. 
The best textile materials, which are bast-fibers of various 
plants, viz., common hemp, manilla-hemp, (Miisa textilis,) 
aloe-hemp, (Agave Americana,) common flax, and New 
Zealand flax, {Phormium, tenax^ are completely incrusted 
with silica. In jute, {Corchorus textilis,) some cells are 
partially incrusted. The cotton fiber is free from silica. 
Wicke, (loc. cit.,) suggests that the durability of textile 
fibers is to a degree dependent on their content of silica. 

The great variableness observed in the same plant, and 
in the same part of the plant, as to the content of silica, 
would indicate that this substance is at least in some de- 
gree accidental. 

In the ashes of ten kinds of tobacco leaves, Fresenius 
& Will found silica to range from 5.1 to 18.4 per cent. 
The analysis of the ash of 13 samples of pea-straw, grown 
on different soils from the same seed during the same year, 
under direction of the " Landes Oeconomie Collegium," of 
Prussia, gave the following percentages of silica, viz.: 
0.56; 0.75; 2.30; 2.32; 2.80; 3.29; 3.57; 5.15; 5.82; 
8.03 ; 8.32 ; 9.77 ; 21.35. Analyses of the ash of 9 samples 
of colza-straw, all produced from the same seed on differ- 
ent soils, gave the following percentages : 1.00 ; 1.14 ; 3.02 ; 
3.57 ; 4.65 ; 5.08 ; 7.81 ; 11.88 ; 17.12. {Journal furpraJct. 



186 HOW CEOPS GEOW. 

Chem., xlviii, 474-7.) Such instances might be greatly 
multiplied. 

The idea that a part of the silica is accidental is further 
sustained by the fact observed by Saussure, the earliest in- 
vestigator of the composition of the ash of plants, {Re- 
cherches sur la Vegetation, p. 282,) that crops raised on a 
silicious soil are in general richer in silica than those grown 
on a calcareous soil. Norton found in the ash of the chaff 
of the Hopeton oat from a light loam 56.7 per cent, from 
a poor peat soil 50.0 of silica, while the chaff of the potato- 
oat from a sandy soil gave 70.9 per cent. 

Salm-Horstmar obtained some remarkable results in the 
course of his synthetical experiments on the mineral food 
of plants, which fully confirmed him in the opinion that 
silica is indispensable to vegetation. He found that an 
oat plant, having for its soil pure quartz, (insoluble silica,) 
with addition of the elements of growth, soluble silica ex- 
cepted, not only grew well, but contained in its ash 23° !„ 
of silica, or as great a proportion as exists in the plant 
raised under normal conditions. This silica may, however, 
have been mostly derived from the husk of the seed, for 
the plant was a very small one. 

Sachs, in 1862, was the first to publish evidence indi- 
cating strongly that silica is not a necessary ingredient of 
maize. He obtained in his early essays in water-culture a 
maize plant of considerable development, whose ashes con- 
tained but 0.7° 1 of silica. Shortly afterwards, Knop pro- 
duced a maize plant with 140 ripe seeds, and a dry-weight 
of 50 grammes, (nearly 2 oz. av.,) in a medium so free from 
silica that a mere trace of this substance could be found in 
the root, but half a milligramme in the stem, and' 22 milli- 
grammes in the 15 leaves and sheaths. It was altogether 
absent from the seeds. The ash of the leaves of this plant 
thus contained but 0.54 per cent of silica, and the stem 
but 0.07 per cent. Way & Ogston found in the ash of. 
maize, leaf and stem together, 27.98 per cent of silica. 



THE ASH OF PLANTS. 187 

Knoj) inclined to believe that the little silica he found 
in his maize plant was due to dust, and did not belong to 
the tissues of the plant. He remarked, "I believe that 
silica is not to be classed among the nutritive elements of 
the Gramineae, since I have made similar observations in 
the analysis of the ashes of barley." 

In the numerous experiments that have been made more 
recently upon the growth of plants in aqueous solutions, 
by Sachs, Knop, Kobbe & Siegeit, Stohmann, Kauten- 
berg & Kiihn, Birner & Lucanus, Leydhecker, Wolff, 
and Harape, silica, in nearly all cases, has been excluded, so 
far as it is possible to do so in the use of glass vessels. 
This has been done without prejudice to the development 
of the plants. N'obbe & Siegert and Wolff especially 
have succeeded in producing buckwheat, maize, and the 
oat, in full perfection of size and parts, with this exclusion 
of silica. 

Wolff, ( Vs. St., YIII, p. 200,) obtained in the ash of 
maize thus cultivated, 2-3° |g of silica, Avhile the same two 
varieties from the field contained in their ash 11|-13''|q. 
The proportion of ash was essentially the same in both 
cases, viz., about 6°|„. Wolff's results with the oat plant 
were entirely similar. Birner & Lucanus, ( Vs. St., YIII, 
141,) found that the supply of soluble silicates to the oat 
made its ash very rich in silica, (40° |^,) but diminished the 
growth of straw, Avithout affecting that of the seed, as 
compared with plants nearly destitute of silica. 

While it is not thus demonstrated that utter absence of 
silica is no hindrance to the growth of plants which are 
ordinarily rich in this substance, it is certain that very 
little will suffice their needs, and highly probable that it 
is in no way essential to their physiological development. 

The Ash-Ingredients, which are indispensable to Crops, 
may he taken up in larger quantity than is essential. — 

More than sixty years ago, Saussure described a simple 



188 HOW CEOPS GEOW. 

experiment which is conclusive on this point. He gathered 
a number of peppermint plants, and in some determined 
the amount of dry-matter, which was 40.3 per cent. The 
roots of others were then immersed in pure water, and the 
plants were allowed to vegetate 2^ months in a place ex- 
l^osed to air and light, but sheltered from rain. 

At the termination of the experiment, the plants, which 
originally weighed 100, had increased to 216 parts, and 
the dry matter of these plants, which at first was 40.3, had 
become 62 parts. The plants could have acquired from 
the glass vessels and pure water no considerable quantity of 
mineral matters. It is plain, then, that the ash-ingredients 
which were contained in two parts of the peppermint were 
sufficient for the production and existence of three parts. 
We may assume, therefore, that at least one-third of the 
ash of the original plants was in excess, and accidental. 

The fact of excessive absorption of essential ash-in- 
gredients is also demonstrated by the precise experiments 
of Wolff on buckwheat, already described, (see p. 164,) 
where the point in question is incidentally alluded to, and 
the difficulties of deciding how much excess may occur, 
are brought to notice. (See also pp. 176 and 179 in regard 
to potash and oxide of iron.) 

As a further striking instance of the influence of the 
nourishing medium on the quantity of ash-ingredients in 
the plant, the following is adduced, which may serve to 
put in still stronger light the fact that a plant does not 
always require what it contains. 

Nobbe & Siegert have made a comparative study of 
the composition of buckwheat, grown on the one hand in 
garden soil, and on the other in an aqueous solution of 
saline matters. (The solution contained sulphate of mag- 
nesia, chloride of calcium, phosj^hate and nitrate of potash, 
with phosphate of iron, which together constituted 0.316° \^ 
of the liquid.) The ash-percentage was much higher in 



THE ASH OP PLANTS. 189 

the water-plants than in the garden-plants, as shown by the 
subjoined figures. {Vs. jSt., Y, p. 132.) 

Per cent of ash in 

Stems and Leaves. Roots. Seeds. Entire Plant. 

Water-pLant 18.6 15.3 2.6 16.7 

Garden-plant.... 8.7 6.8 2.4 7.1 

We have seen that well-developed plants contain a 
larger proportion of ash than feeble ones, when they grow 
side by side in the same medium. In disregard of this 
general rule, the water-plant in the present instance has 
an ash-percentage double that of the land-plant, although 
the former was a dwarf compared with the latter, yielding 
but ^le as much dry matter. The seeds^ however, are 
scarcely different in composition. 

Disposition by the Plant of excessive or superfluous 

ash-in^redientSi — The ash-ingredients taken up by a plant 
in excess beyond its actual wants may be disposed of in 
three ways. The soluble matters — those soluble by them- 
selves, and also incapable of forming insoluble combina- 
tions with other ingredients of the plant — viz., the alkali 
chlorides, sulphates, carbonates, and phosphates, the 
chlorides of calcium and magnesium, may — 

1., Remain dissolved in, and diffused throughout, the 
juices of the plant ; or, 

2.9 May exude upon the surface as an efflorescence, and 
be washed off by rains. 

Exudation to the surface has been repeatedly observed 
in case of cucumbers and other kitchen vegetables, grow- 
ing in the garden, as well as with buckwheat and barley 
in water-culture. ( Ys. St., VI, p. 37.) 

Saussure found in the white incrustations upon cucum- 
ber leaves, besides an organic body insoluble in water 
and alcohol, chloride of calcium, with a trace of chlo- 
ride of magnesium. The organic substance so enveloped 
the chloride of calcium as to prevent deliquescence of 
the latter. [Becherches siir la Veg., p. 265.) 



190 HOW CROPS GROW. 

Saussure proved that foliage readily yields up saline 
matters to water. He placed hazel leaves eight successive 
times in renewed portions of pure water, leaving them 
therein 15 minutes each time, and found that by this treat- 
ment they lost ^| ^^ of their ash-ingredients. The por- 
tion thus dissolved was chiefly alkaline salts; but con- 
sisted in part of earthy phosphates, silica, and oxide of 
iron. {Recherches, p. 287.) 

Ritthausen has shown that clover which lies exposed to 
rain after being cut, may lose by washing more than ^| 3 
of its ash-ingredients. 

Mulder, ( Chemie der Aclcerhrume, II, p. 305,) attributes 
to loss by rain a considerable share of the variations in per- 
centage and composition of the fixed ingredients of plants. 
We must not, however, forget that all the experiments 
which indicate great loss in this way, have been made on 
the cut plant, and their results may not hold good to the 
same extent for uninjured vegetation, which certainly does 
not admit of soaking in water. Further investigations 
must decide this point. 

3i The insoluble matters, or those which become insolu- 
ble in the jDlant, viz., the sulphate of lime, the oxalates, phos- 
phates, and carbonates of lime and magnesia, the oxides of 
iron and manganese, and silica, may be deposited as crys- 
tals or concretions in the cells, or may incrust the cell- 
walls, and thus be set aside from the spliere of vital 
action. 

In the denser and comparatively juiceless tissues, as in 
bark, old wood, and ripe seeds, we find little variation in 
the content of soluble matters. These are present in large 
and variable quantity only in the succulent organs. 

In bark, (cuticle,) wood, and seed envelopes, (husks, 
shells, chaff,) we often find silica, the oxides of iron and 
manganese, and carbonate of lime — all insoluble substances 
— accumulated in considerable amount. In bran — ^the 
cuticle of the kernels of cereals — ^phosphate of magnesia 



THE ASH OF PLANTS. 



191. 



exists in comparatively large quantity. In the dense teak 
wood, concretions of phosphate of lime have been noticed. 
Of a certain species of cactus, {Cactus senilis^ S^^L ^^ 
the dry matter consists of crystals, probably a lime salt. 

That the quantity of matters thus segregated is in some 
degree proportionate to the excess of them in the nourish- 
ing medium in which the plant grows has been observ- 
ed by Nobbe & Siegert, who remark that the two por- 
tions of buckwheat, cultivated by them in solutions and 
in garden soil respectively, (p. 188,) both contained crys- 
tals and globular crystalline masses, consisting probably 
of oxalates and phosphates of lime and magnesia, depos- 
ited in the rind and pith; hut that these loere hy far most 
abundant hi the water-plants^ whose ash-percentage loas 
twice as great as that of the land-plants. 

These insoluble substances may either be entirely unes- 
sential, as appears to be the case with silica, or, having 
once served the wants of the plant, may be rejected as no 
longer useful, and by assuming the insoluble form, are re- 
moved from the sphere of vital action, and become as good 
as dead matter. They are, in fact, excreted, though not, 
in general, formally expelled be- 
yond the limits of the plant. They 
are, to some extent, thrown off into 
the bark, or into the older wood 
or pith, or else are virtually en- 
cysted in the living cells. 

The occurrence of crystallized 
salts thus segregated in the cells 
of plants is illustrated by the 
following cuts. Fig. 23 represents 
a crystallized concretion of oxalate 
of lime, having a basis or skeleton of cellulose, from a leaf 
of the walnut. (Payen, Chimie Industrielle Fl.Xll.) Fig. 
24 is a mass of crystals of a lime salt, from the leaf stem 
of rhubarb. Fig. 25, similar crystals from the beet root. 



^^br3 




192 



HOW CROPS GROW. 




In the root of the young bean, Sachs found a ring of cells, , 
containing crystals of sulphate of lime. {Sitzimgsherichte 

der Wien. AJcacl, 37, p. 106.) 
Bailey observed in certain 
parts of the inner bark of the 
locust a series of cells, each 
of which contained a crystal. 
In the onion-bulb, and many 
Fig. 24. Fig. 25. oi^her plants, crystals are 

abundant. ( Gray's Struct. Botany, 5th Ed., p. 59.) 

Instances are not wanting in which there is an obvious 
excretion of mineral matters, or at least a throwing of 
them off to the surface. Silica, as we have seen, is often 
found in the cuticle, but it is usually imbedded in the cell- 
wall. In certain plants, other substances accumulate in 
considerable quantity without the cuticle. A striking ex- 
ample is furnished by the Saxifraga crusta, a low European 
plant, which is found in lime soils. 
The leaves of this saxifrage are 
entirely coated with a scaly in- 
crustation of carbonate of lime 
and carbonate of magnesia. At 
the edges of the leaf, this incrusta- 
tiofl acquires a considerable thick- 
ness, as is illustrated by figure 26, 
a. In an analysis made by linger, 
to whom these facts are due, the 
fresh, (undried,) leaves yielded to 
a dilute acid 4.14° 1^ of carbonate 
of lime, and 0.82° 1^ of carbonate 
of magnesia. 

linger learned by microscopic 
investigation that this excretion of carbonates proceeds 
mostly from a series of glandular expansions at the margin 
of the leaf, which are directly connected with the sap-ducts 
of the plant. {Sitz^herichte der Wien. Akad., 43, p. 519.) 




d 

Fig. 26. 



THE ASH OF PLAiq^TS. 193 

In figure 26, a represents the appearance of a leaf, inagnified 4X diam- 
eters. Around the borders are seen the scales of carbonate of lime ; 
some of these have been detached, leaving round pits on the surface of 
the leaf: c, d^ exhibit the scales themselves, e in profile : & shows a leaf, 
freed from its incrustation by an acid, and from its cuticle by potash- 
solution, so as to exhibit the veins, (ducts,) and glands, whose course 
the carbonate of lime chiefly takes in its passage through the plant. 

Further as to the state of ash-ingredients. — ^It is by no 

means true that the ash-ingredients always exist in plants 
in the forms under which they are otherwise familiar 
to us. . 

Arendt and Hellriegel have studied the proportions of 
soluble and insoluble matters, the former in the ripe oat 
plant, and the latter in clover at various stages of growth. 

Arendt extracted from the leaves and stems of the oat- 
plant, after thorough grinding, the whole of the soluble 
matters by repeated washings with water.* He found that 
all the sulphuric acid and all the chlorine were soluble. 
^NTearly all the phosphoric acid was removed by water. The 
larger share of the lime, magnesia, soda, and potash, was 
soluble, though a portion of each escaped solution. Oxide 
of iron was found in both the soluble and insoluble state. 
In the leaves, iron was found among the insoluble matters 
after all phosphoric acid had been removed. Finally, silica 
was mostly insoluble, though in all cases a small quantity 
occurred in the soluble condition, viz., 3-8 parts in 10,000 
of the dry plant. (Wachsthum der Haferpflanze^ pp. 168, 
183-4. See, also, table on p. 198.) 

Weiss and Wiesner have found by microchemical investi- 
gation that iron exists as insoluble compounds of protox- 
ide and sesquioxide, both in the cell-membrane and in the 
cell-contents. [Sitz^berichte der Wiener Akad.^ 40, 278.) 

Hellriegel found that a larger proportion of the various 
bases was soluble in young clover than in the mature 
plant. As a rule, the leaves gave most soluble matters, 



To extract the soluble parts of the grain in this way was impossible. 

9 



194 HOW CEOPS GEOW. 

the leaf-stalks less, and the stems least. He obtained, 
among others, the following results. ( Vs. St., lY, p. 59.) 
Of 100 parts of the following fixed ingredients of clover, 
were dissolved in the sap, and not dissolved — 

In young leaves. In full-grown leaves. 

•D^+n.T, (dissolved 75.2 37.3 

rotash j undissolved 24.8 62.7 

T^^ (dissolved 69.5 72.4 

Lime j undissolved 30.5 27.6 

TVT„^v,«o-„ i dissolved 43.6 78.3 

Magnesia j undissolved 56.4 21.7 

Phosphoric ( dissolved 20.9 19.9 

acid (undissolved 79.1 80.1 

Q.,. (dissolved 26.8 16.1 

foUica j undissolved 73.2 83.9 

These researches demonstrate that potash and soda — 
bodies, all of whose commonly occurring compounds, sili- 
cates excepted, are readily soluble in water — enter into 
insoluble combinations in the plant ; while phosphoric acid, 
which forms insoluble salts with lime, magnesia, and iron, 
is freely soluble in connexion with these bases in the sap. 

It should be added that sulphates may be absent from 
the plant or some parts of it, although they are found in 
the ashes. Thus Arendt discovered no sulphates in the 
lower joints of the stem of oats after blossom, though in 
the upper leaves, at the same period, sulphuric acid, (S O3,) 
formed nearly T\^ of the sum of the fixed ingredients. 
( Wachsthum der Haferpf.^ p. 157.) Ulbricht found that 
sulphates were totally absent from the lower leaves and 
stems of red clover, at a time when they were present 
in the upper leaves and blossom. ( Vs. St., IV", p. 30, Ta- 
belle.) Both Arendt and Ulbricht observed that sulphur 
existed in all parts of the plants they experimented upon; 
in the parts just specified, it was, however, no longer com- 
bined to oxygen, but had, doubtless, become an integral 
part of some albuminoid or other complex organic body. 
Thus the oat stem, at the period above cited, contained a 
quantity of sulphur, which, had it been converted into 
sulphuric acid, would have amounted to 14° 1^ of the fixed 



THE ASH OF PLANTS. 195 

ingredients. In the clover leaf, at a time when it was 
totally destitute of sulphates, there existed an amount of 
sulphur, which, in the form of sulphuric acid, would have 
made 13.7° 1^, of the fixed ingredients, or one per cent of 
the dry leaf itself.* 

Other ash-ingredients. — Salm-Horstmar has described 
some experiments, from which he infers that a minute 
amount of Lithia and Fluorine^ (the latter as fluoride of 
potassium,) are indispensable to the fruiting of barley. 
{Jour, fur prakt. Ghem., 84, p. 140.) The same observer, 
some years ago, was led to conclude that a trace of Titanic- 
acid is a necessary ingredient of plants. The later results 
of water-culture would appear to demonstrate that these 
conclusions are erroneous. 

It is, however, possible, as Mulder has suggested, ( Che- 
mie der AcJcerJcrume, 11, 341,) that the failure of certain 
crops, after long-continued cultivation in the same soil, 
may be due to the exhaustion of some of these less abun- 
dant and usually overlooked substances. Land not unfre- 
quently becomes "clover-sick," i. e., refuses to produce 
good crops of clover, even with the most copious manur- 
ings. In Vaucluse, according to Mulder, the madder crop 
has suffered a deterioration in quality — the coloring effect 
of the root having diminished one-fourth — as an apparent 
result of long cultivation on the same soil, although the 
seed is annually renewed from Asia Minor, and great care 
is bestowed on its culture. 

The newly discovered element, Huhidium,, has been 
found in the sugar-beet, in tobacco, coffee, tea, and the 



* Arendt was the first to estimate sulphuric acid in vegetable matters with 
accuracy, and to discriminate it from the sulphur in organic compounds. Tliis 
chemist determined the sulphuric acid of the oat-plant by extracting the pulver- 
ized material with acidulated water. He likewise estimated the total sulphur by 
a special method, and by subtracting the sulphur of the sulphuric acid from the 
total, he obtained as a difference that portion of sulphur which belonged to the 
albuminoids, etc. In his analyses of clover, Vlbricht followed a similar plan. 
(ys. St., Ill, p. 147.) As has already been stated, many of the older analyses 
are wholly mitrustworthy as regards sulphur and sulphuric acid. 



196 HOTV CROPS GKOW. 

grape. It doubtless occurs perhaps, together with Cae- 
sium, in many other plants, though in very minute quan- 
tity. It is not unlikely that small quantities of these 
alkali-metals may be found to be of decided influence on 
the growth of plants.* 

The late investigations of A Braun and of Risse, (Sachs, 
JSxp. Physiologie, l^^O show that Zhio is a usual ingre- 
dient of plants growing about zinc mines, where the soil 
contains carbonate or silicate of this metal. Certain mark- 
ed varieties of plants are peculiar to, and appear to have 
been produced by, such soils, viz., a violet, ( Viola tricolor^ 
var. calaminans,)\ and a shepherd's purse, (Thlaspi al- 
pestre, var. calaminaris?) In the ash of the leaves of the 
latter plant, Risse found 13° |o of oxide of zinc; in other 
plants he found from 0.3 to 3.3" |,. 

Copper is often or commonly found in the ashes of 
plants ; and other elements, wiz,, Arsenic, Baryta^2^ndi Lead^ 
have been discovered therein, but as yet we are not fairly 
warranted in assuming that any of these substances are of 
importance to agricultural vegetation. The same is true 
of Iodine, which, though an invariable and probably a 
necessary constituent of many algse, is not known to exist 
to any considerable extent or to be essential in any culti- 
vated plants. 

§ 4. 
FUNCTIONS OF THE ASH-INGREDIENTS. 

But little is certainly known with reference to the 
subject of this section. 

Sulphates. — ^The albuminoids, \vhich contain sulphur as 
an essential ingredient, obviously cannot be produced in 
absence of sulphuric acid, which, so far as we know, is the 

* Since the above was written, Birner «fc Lucamis have found that these 
"bodies, in the absence of potash, act as poisons to the oat. {Vs. /St., YUI, p. 147.) 
t By some botanists ranked as a distinct species. 



THE ASH OF PLANTS. 197 

single source of sulphur to plants. The sulphurized oils 
of the onion, mustard, horseradish, turnip, etc., likewise 
require sulphates for their organization. 

Phosphates* — The phosphorized oils (protagon) require 
to their elaboration that phosphates or some source of 
phosphorus be at the disposal of the plant. The physio- 
logical function of the phosphates, so abundant in the ce- 
reals, admits of partial explanation. The soluble albumi- 
noids which are formed in the foliage must pass thence 
through the cells and ducts of the stem into growing parts 
of the plant, and into the seed, where they accumulate in 
large quantity. But the albuminoids penetrate membranes 
with great difficulty and slowness when in the pure state. 
According to Schumacher, (Physik der Pflanze^ p. 128,) 
the phosphate of potash considerably increases the diffu- 
sive rate of albumin, and thus facilitates its translocation 
in the plant. 

Alkalies and alkali-earths. — The organic acids, viz. : 
oxalic, malic, tartaric, citric, etc., require alkalies and al- 
kali-earths to form the salts which exist in plants, e. g. bi- 
tartrate of potash in the grape, oxalate of lime in beet- 
leaves, raalate of lime in tobacco ; and without these bases 
it is, perhaps, in most cases impossible for the acids to be 
formed, though in the orange and lemon, citric acid exists 
in the uncombined or free state, and in various plants, as 
JSempervivum arhoreum^ and Cacalia ficoides^ acids are 
formed during the night which disappear in the day. The 
leaves of these plants are sour in the morning, tasteless at 
noon, and bitter at night. (Heyne <fc Link).) 

Silica. — The function of silica might appear to be, in case 
of the grasses, sedges, and equisetums, to give rigidity to 
the slender stems of these plants, and enable them to sustain 
the often heavy weight of the fruit. Two circumstances, 
however, embarrass the unqualified acceptance of this no- 
tion. The first is, that the proportion of silica is not great- 



198 HOW CROPS GEOW. 

est in those parts of the plant which, on this view, would 
most require its presence. Thus Norton, (Am. Jour, of 
Sci., [2,] vol. iii, pp. 235-6,) found that in the sandy oat 
the upper half of the dry leaf yielded 16.2 per cent ash, 
while the lower half gave but 13.6 per cent. The ash of 
the upper part contained 52.1 per cent of silica, while that 
from the bottom part had but 47.8 per cent of this ingre- 
dient. According to Arendt, (Das Wachsthum der Ma- 
ferpflanze, p. 180,) the different parts of the oat contain 
the following quantities of silica respectively : 

Amount of silica in 1000 parts of dry substance. 

Removed Insoluble 

hy water. in water. Total. 

Lower part of the stem 0.33 1.4 1.7 

Middle part of the stem.... 0.30 4.8 5.1 

Upper part of the stem 0.36 13.0 13.3 

Lower leaves 0.86 34.3 35.3 

Upper leaves 0.52 43.3 43.8 

We see then, plainly, that the upper part of the stem 
and leaves contains more silica than the lower parts, while 
the lower parts certainly need to possess the greatest 
de2;ree of strensjth. 

We must not forget, however, as Knop has remarked, 
that the lower part of the leaf of most cereals and grasses 
which envelopes the stem like a sheath, is really the support 
of the plant as much as, or even more, than the stem itself. 

The results of the many experiments in water-culture 
by Sachs, Knop, Wolff, and others, (see p. 186,) in which 
the supply of silica has been reduced to an extremely 
small amount, without detriment to the development of 
plants, commonly rich in this substance, would seem to 
demonstrate that silica does not essentially contribute to 
the stiffness of the stem. 

Wolff distinctly informs us that the maize and oat plants 
produced by him, in solutions nearly free from silica, 
were as firm in stalk, and as little inclined to lodge or 
" lay," as those which grew in the field. 



THE ASH OP PLANTS. 199 

The recommendation to supply silex to grain crops, in 
order to stiffen the straw and prevent falling of the crop 
before it ripens, either by directly applying alkali-silicates, 
or by the use of fertilizers and amendments that may 
render the silica of the soil soluble, must, accordingly, be 
considered entirely futile from the point of view of the needs 
of the crop, as it is from that of the resources of the soil. 

Chlorine t — As has been mentioned, both Nobbe and 
Leydhecker found that buckwheat grew quite well up to 
the time of blossom without chlorine. From that period 
on, in absence of chlorine, remarkable anomalies appeared 
in the development of the plant. In the ordinary course 
of growth, starch, which is organized in the mature leaves, 
does not remain in them to much extent, but is transferred 
to the newer organs, and especially to the fruit, where it 
also accumulates in large quantities. In absence of chlo- 
rine, in the experiments of JSTobbe and Leydhecker, the 
terminal leaves became thick and fleshy, from extraordinary 
development of cell-tissue, at the same time they curled 
together and finally fell off, upon slight disturbance. The 
stem became knotty, transpiration of water was suppress-* 
ed, the blossoms withered without fructification, and the 
plant prematui-ely died. The fleshy leaves were full of 
starch-grains, and it appeared that in absence of chlorine 
the transfer of starch from the foliage to the flower and 
fruit was rendered impossible ; in other words, chlorine (in 
combination with potassium or calcium) was concluded to 
be necessary to, was, in fact, the agent of this transfer. 
Knop believes, however, that these phenomena are due to 
some other cause, and that chlorine is not essential to the 
perfection of the fruit of buckwheat, (see p. 182). 

Iron* — ^We are in possession of some interesting facts, 
which appear to throw light upon the function of this 
metal in the plant. In case of the deficiency of this ele- 
ment, foliage loses its natural green color, and becomes pale 
or white even in the full sunshine. In absence of iron a 



200 HOW CEOPS GEOW. 

plant may unfold its buds at the expense of already organ- 
ized matters, as a potato-sprout lengthens in a dark cellar, 
or in the manner of fungi and white vegetable parasites ; 
but the leaves thus developed are incapable of assimilating 
carbon, and actual growth or increase of total weight is 
impossible. Salm-Horstmar showed that plants which 
grow in soils or media destitute of iron, are very pale in 
color, and that addition of iron-salts very speedily gives 
them a healthy green. Sachs found that maize-seedlings, 
vegetating in solutions free from iron, had their first three 
or four leaves green ; several following were white at the 
base, the tips being green, and afterward, perfectly white 
leaves unfolded. On adding a few drops of sulphate or 
chloride of iron to the nourishing medium, the foliage was 
plainly altered within 24 hours, and in 3 to 4 days the 
plant acquired a deep, lively green. Being afterwards 
transferred to a solution destitute of iron, perfectly white 
leaves were again developed, and these were brought to a 
normal color by addition of iron. 

E. Gris was the first to trace the reason of these efiects, 
and first found, (in 1843,) that watering the roots of plants 
with solutions of iron, or applying such solutions exter- 
nally to the leaves, shortly developed a green color where 
it was previously wanting. By microscopic studies he 
found that in the absence of iron, the protoplasm of the 
leaf-cells remains a colorless or yellow mass, destitute of 
visible organization. Under the influence of iron, grains 
of chlorophyll begin at once to appear, and pass through 
the various stages of normal development. We know 
that the power of the leaf to decompose carbonic acid and 
assimilate carbon, resides in the cells that contain chloro- 
phyll, or, we may say, in the chlorophyll-grains themselves. 
We understand at once, then, that in the absence of iron, 
which is essential to the formation of chlorophyll, there 
can be no proper growth, no increase at the expense of the 
external atmospheric food of vegetation. 



QUANTITATIVE BELATIONS. 201 

Risse, under Sachs' direction, {JExp. Physiologie^ 143,) 
demonstrated that manganese cannot take the place of 
iron in the office just described. 

Functions of other Ash-In^redients* — As to the spe- 
cial uses of the other fixed matters we know little. It ap- 
pears to be proved beyond doubt that potash, lime, and 
magnesia, are indispensable to the life and health of ani- 
mals, and since all animals derive the chief part of their 
sustenance from the vegetable world, it is obvious that 
these substances must be ingredients of plants in order to 
fit the latter for their nutritive ofiice ; but why no vegeta- 
ble cell can be elaborated without potash, why lime and 
magnesia are imperative necessities to plants, we are as 
yet not able to comprehend. 



CHAPTER ni. 



QUANTITATIVE RELATIONS AMONG THE INGREDIENTS 
OF PLANTS. 

Various attempts have been made to exhibit definite 
numerical relations between certain different ingredients 
of plants. 

Equivalent Replacement of Bases* — ^In 1840, Liebig, 
in his Chemistry applied to Agriculture, suggested that 
the various bases might displace each other in equivalent 
quantities, i. e., in the ratio of their molecular weights, 
and that were such the case, the discrepancies to be observ- 
ed among analyses should disappear, if the latter were in- 
terpreted on this view. Liebig instanced two analyses of 
the ashes of fir-wood and two of pine-wood made by Ber- 
thier and Saussure, as illustrations of the correctness of 
this theory. In the fir of Mont Breven, carbonate of 
9* 



202 HOW CHOPS geow. 

magnesia was present ; in that of Mont La Salle, it was ab- 
sent. In the former existed but half as much carbonate 
of potash as in the latter. In both, however, the same 
total percentage of alkali and earthy carbonates was 
found, and the amount of oxygen in these bases was the 
same in both instances. 

Since the unlike but equivalent quantities of potash, lime, 
and magnesia, contain the same quantity of oxygen, these 
bases, in the case in question, do displace each other in 
equivalent proportions. The same was true for the ash of 
pine-wood, from Allevard and from Norway. On apply- 
ing this principle to other cases it has, however, signally 
failed. The fact that the plant can contain accidental or 
unessential ingredients, renders it obvious that, however 
truly such a law as that of Liebig may in any case apply 
to those substances which are really concerned in the vital 
actions, it will be impossible to read the law in the results 
of analyses. 

Relation of Phosphates to Albuminoids. — Liebig like- 
wise considers that a definite relation must and does exist 
between the phosphoric acid and the albuminoids of the 
ripe grains. That this relation is not constant, is evident 
from the following statement of the data, that have been 
as yet obtained, bearing on the question. In the table, 
the amount of nitrogen (N), representing the albuminoids 
(see p. 108) found in various analyses of rye and wheat 
grain, is compared with that of phosphoric acid (POJ, 
the latter being taken as unity. 

PO5 

In 7 Samples of Eye-kernel Fehling & Faiszt found the ratio of 

PO 5 to N to range from 1 

do do Mayer do do do 1 

do do Bibra do do do 1 

do do Siegert do do do 1 

do do the extreme range was from 1 

of Wheat-kernel Fehling & Faiszt found the ratio of 

PO5 to N to range from 1 

do do • Mayer do do do 1 

do do Zoeller do do do 1 

do do Bibra do do do 1 

do do Siegert do do do 1 

do do the extreme range was from 1 : 1.83—3.55 



doll 


do 


do 5 


do 


do 6 


do 


do 28 


do 


do 2 


do 


doll 


do 


do 2 


do 


do 30 


do 


do 6 


do 


do 51 


do 




compositio:n- in successive stages. 203 

Siegert, who has collected these data, ( Vs. St., Ill, 147,) 
and who experimented on the influence of phosphatic 
and nitrogenous fertilizers upon the composition of wheat 
and rye, gives as the general result of bis special inquiries, 
that JPhosphorie acid and Nitrogen stand in no constant 
relation to each other. JSPitrogetious manures increase the 
per cent of nitrogen and diminish that of phosphoric 
acid. 

Other Relations I — ^AU attempts to trace simple and 
constant relations between other ingredients of plants, 
viz. : between starch and alkalies, cellulose and silica, etc., 
etc., have proved fruitless. 

It is much rather demonstrated that the proportions of 
the constituents is constantly changing from day to day 
as the relative mass of the individual organs themselves 
undergoes perpetual variation. 

In adopting the above conclusions, it is not asserted 
that such genetic relations between phosphates and al- 
buminoids, or between starch and alkalies, as Liebig first 
suggested and as various observers have labored to show, 
do not exist, but simply that they do not appear from 
the analyses of plants. 

§3. 

THE COMPOSITION OF THE PLANT IN SUCCESSIVE 
STAGES OF GROWTH. 

"W"e have hitherto regarded the composition of the plant 
mostly in a relative sense, and have instituted no compari- 
sons between the absolute quantities of its ingredients at 
different stages of growth. We have obtained a series of 
isolated views of the entire plant, or of its parts at some 
certain period of its life, or when placed under certain con- 
ditions, and have thus sought to ascertain the peculiarities 
of these periods and to estimate the influence of these con- 



204 HOW CROPS GEOW. 

ditions. It now remains to attempt in some degree the 
combination of these sketches into a panoramic picture — 
to give an idea of the composition of the plant at the 
successive steps of its development. We shall thus gain 
some insight into the rate and manner of its growth, and 
acquire data that have an important bearing on the requi- 
sites for its perfect nutrition. For this purpose we need 
to study not only the relative (percentage) composition 
of the plant and of its parts at various stages of its exist- 
ence, but we must also inform ourselves as to the total 
quantities of each ingredient at these periods. 

We shall select from the data at hand those which illus- 
trate the composition of the oat-plant. Not only the ash- 
ingredients, but also the organic constituents, will be no- 
ticed so far our information and space permit. 

The Composition and Growth of the Oat-Plant may 

be studied as a type of an important class of agricultural 
plants, viz. : the annual cereals — plants which complete 
their existence in one summer, and which yield a large 
quantity of nutritious seeds — the most valuable result of 
culture. The oat-plant was first studied in its various 
parts and at different times of development by Prof John 
Pitkin Norton, of Yale College. His laborious research 
published in 1846, {Trans. S'lghland andAg. 8oc. 1845-7, 
also Am. Jour, of Sci. and Arts, Yol. 3, 1847,) was the 
first step in advance of the single and disconnected anal- 
yses which had previously been the only data of the agri- 
cultural physiologist. For several reasons, however, the 
work of Norton was imperfect. The analytical methods 
employed by him, though the best in use at that day, and 
handled by him with great skill, were not adapted to fur- 
nish results trustworthy in all particulars. Fourteen years 
later, Arendt,* at Moeckern, and Bretschneider,t at Saarau, 



* WachsthumsverMltnisse der Haferpflanze, Jour, fur PraM. Cliem., %, 19Z. 
t Das Wachsthum der Haferjyflanse, Leipzig. 1859. 



COMPOSITION IN SUCCESSIVE STAGES. 205 

in Germany, at the same time, but independently of each 
other, resumed the subject, and to their labors the sub- 
joined figures and conckisions are due. 

Here follows a statement of the Periods at which the 
plants were taken for analysis. 

I June 18, Arendt— Three lower leaves unfolded, two upper still closed. 
1st Period j- k>. iq^ Bretschneider— Four to five leaves developed. 
21 P • d i "^"^^ ^^' (^^ ^^y^'^ At.— Shortly before the plants were fully headed. 

-t^erio |- ^^ gg^ ^^^ days,) Br.— The plants were headed. 
„ , p , , ) July 10, (10 days,) At.— Immediately after bloom. 
da rerioQ j- ^^ ^^ ^^ ^^^^.^ Br.— Full bloom. 

4th Period i'^^^y 21, (11 days,) At.-Beginning to ripen, 
^njr-enottj- ^^ 28, (20 days,) Br.- 
5th Period K^^y 31, (10 days,) At.-Fully ripe. 
) Aug. 6, (9 days,) Br.— " •' 

It will be seen that the periods, though differing some- 
what as to time, correspond almost perfectly in regard to 
the development of the plants. It must be mentioned 
that Arendt carefully selected luxuriant plants of equal 
size, so as to analyze a uniform material, (see p. 210,) and 
took no account of the yield of a given surface of soil. 
Bretschneider, on the other hand, examined the entire 
produce of a square rod. The former procedure is best 
adapted to study the composition of the well-nourished 
individual plant ; the latter gives a truer view of the crop. 

The unlike character of the material as just indicated is 
but one of the various causes which might render the two 
series of observations discrepant. Thus, differences in 
soil, weather, and seeding, would necessarily influence the 
relative as well as the absolute development of the two 
crops. The results are, notwithstanding, strikingly accord- 
ant in many particulars. In all cases the roots were not 
and could not be included in the investigation, as it is im- 
possible to free them from adhering soil. 

The Total Weight of Crop per English acre, at the 

end of each period, was as follows : 



206 HOW CROPS GROW. 

Table I.— Br. 
1st Period, 6,358 lbs. avoirdupois. 
2d " 10,603 " 
3d " 16,523 " » 

4th " 14,981 " " 

5th " 10,622 " " 

The Total Weights of Water and Dry Matter for all 

but the 2d Period — the material of which was accidentally 
lost — were : 

Table II.— Br. 

Dry Matter^ Water, 

lbs. av. per acre. lbs. av. per acre. 
1st Period, 1,284 5,074 

3d " 4,383 12,240 

4th " 5,427 14,983 

5th " 6,886 3,736 

1. — ^From Tab. I it is seen : That the weight of the live 
crop is greatest at or before the time of blossom.* After 
this period the total weight diminishes as it had previously 
increased. 

2. — From Tab. II it becomes manifest : That the organic 
tissue (dry matter) continually increases in quantity up to 
the maturity of the plant ; and 

3. — The loss after the 3d Period falls exclusively upon 
the water of vegetation. At the time of blossom the plant 
has its greatest absolute quantity of water, while its least 
absolute quantity of this ingredient is found when it is 
fully ripe. 

By taking the difference between the weights of any 
two Periods, we obtain : 

The Increase or Loss of Dry Matter and Water 
during each Period. 

Table III.— Br. 

Dry Matter, Water, 

lbs. per acre. lbs. per acre. 

1st Period, 1,284 Gain. 5,073 Gain. 

3d " 3,099 " 7,166 " 

4th " 1,044 " 2,684 Loss. 

5th " 1,459 " 5,820 " 

* In Arendt's Experiment, at the time of " heading out," 3d Period. 



COMPOSITION IN- SUCCESSIVE STAGES. 207 

On dividing the above quantities by the number of days 
of the respective j^eriods, there results : 

The Average Daily Gain or Loss per Acre during 
each Period. 

Table IV.— Br. 
Dry Matter. Water, 

1st Period, 22 lbs. Gain. 87 lbs. Gain. 

3d " 163 " '' 382 " " 

4th " 65 " " 167 " Loss. 

5th " 112 " " 447 " " 

4. — Table III, and especially Tab. lY, show that the gain 
of organic matter in Bretschneider's oat-crop Tvent on 
most rapidly at or before the time of blossom, (according 
to Arendt at the time of heading out.) This was, then, the 
period of most active growth. Afterward the rate of 
growth diminished by more than one-half, and at a later 
period increased again, though not to the maximum. 

Absolute Quantities of Carbon, Hydrogen, Oxygen, 
Nitrogen, and Ash, in the dry oat crop at the conclusion of 
the several periods ; {Ihs. per acre.) 

Table V.— Br. 
Carbon. Hydrogen. Oxygen. 
1st Period, 593 80 455 

3d " 2,137 286 1,575 

4th " 2,600 343 2,043 

5th " 3,229 405 2,713 

Relative Quantities of Carbon, Hydrogen, Oxygen, 
Nitrogen, (Organic Matter,) and Ash in the dry oat crop, 
at the end of the several Periods ; i^per cent.) 

Table VI.— Br. 

Carbon. Hydrogen. Oxygen. Nitrogen. {Organic Matter.) Ash. 

1st Period, 46.22 6.23 35.39 3.59 91.43 8.57 

3d "' 48.76 6.53 35.96 2.79 94.04 5.96 

4th " 47.91 6.33 37.65 2.78 94.67 5.33 

5th " 46.89 5.88 39.40 2.43 94.60 5.40 



'itrogen. 


Ash.* 


46 


110 


122 


263 


150 


291 


167 


372 



* In Bretschneider's analyses, " ash" signifies the residue left after carefully 
burning the plant. In Arendt's investigation the sulphur and chlorine were de- 
termiHed in the unburned plant, 



208 HOW CEOPS GROW. 

Relatiye Quantities of Carbon, Hydrogen, Oxygen, 

and Nitrogen, in dry substance, after deducting the some- 
what variable amount of ash, (per cent). 





Table VII.— Br. 








Carbon. Hydrogen. 


Oxygen. 


Nitrogen. 


1st Period, 


50.55 6.81 


38.71 


3.93 


3d " 


51.85 6.95 


38.24 


2.86 


4th " 


50.55 6.96 


39.83 


2.93 


5th " 


49.59 ■ 6.21 


41.64 


2.56 



5. — The Tables Y, YI, and YII, demonstrate that while 
the absolute quantities of the elements of the dry oat 
plant continually increase to the time of ripening, they do 
not increase in the same proportion. In other words, the 
plant requires, so to speak, a change of diet as it advances 
in growth. They further show that nitrogen and ash are 
relatively more abundant in the young than in the mature 
plant ; in other words, the rate of assimilation of Nitrogen 
and fixed ingredients falls behind that of Carbon, Hydro- 
gen, and Oxygen. Still otherwise expressed, the plant as it 
approaches maturity organizes relatively more amyloids 
and relatively less albuminoids. 

The relations just indicated appear more plainly when 
we compare the Quantities of Nitrogen, Hydrogen, and 
Oxygen, assimilated during each period, calculated upon 
the amount of Carbon assimilated in the same time and 
assumed at 100. 

Table VIII.— Br. 





Carbon. 


Nitrogen. 


Hydrogen. 


Oxygen. 


1st Period, 


100 


7.8 


134 


73.6 


3d " 


100 


4.9 


13.3 


72.5 


4th " 


100 


6.1 


12.3 


100.8 


5th " 


100 


2.6 


10.6 


106.5 



From Table YIII we see that the ratio of Hydrogen to 
Carbon regularly diminishes as the plant matures ; that of 
Nitrogen falls greatly from the infancy of the plant to the 
period of full bloom, then strikingly increases during the 



COMPOSITION" IN SUCCESSIVE STAGES. 209 

first stages of ripening, but falls off at last to minimum. 
The ratio of Oxygen to Carbon is the same during the 1st 
and 3d periods, but increases remarkably from the period 
of full blossom until the plant is ripe. 

As already stated, the largest absolute assimilation of 
all ingredients — most rapid growth — takes place at the 
time of heading out, or blossom. At this period all the 
volatile elements are assimilated at a nearly equal rate, 
and at a rate equal to that at which the fixed matters (ash) 
are absorbed. In the first period Nitrogen and Ash ; in 
the fourth period Nitrogen and Oxygen; in the fifth pe- 
riod Oxygen and Ash are assimilated in largest propor- 
tion. 

This is made evident by calculating for each period the 
Daily Increase of Each Ingredient, the amount of the in- 
gredients in the ripe plant being assumed at 100 as a point 
of comparison. The figures resulting from such a calcula- 
tion are given in 

Table IX.— Br. 





Carbon. 


Hydrogen. 


Oxygen. 


Nitrogen. 


Ash, 


1st Period, 


0.31 


0.33 


0.28 


0.47 


0.50 


3d " 


3.51 


2.68 


2.17 


2.39 


2.13 


4th " 


0.89 


0.88 


1.07 


1.06 


0.47 


5th " 


1.49 


1.16 


1.89 


0.75 


1.70 



The increased assimilation of the 5th over the 4th period 
is, in all probability, only apparent. The results of anal- 
ysis, as before mentioned, refer only to those parts of the 
plant that are above ground. The activity of the foliage 
in gathering food from the atmosphere is doubtless greatly 
diminished before the plant ripens, as evidenced by the 
leaves turning yellow and losing water of vegetation. 
The increase of weight in the plant above ground probably 
proceeds from matters previously stored in the roots, which 
now are transferred to the fruit and foliage, and maintain 
the growth of these parts after their power of assimilating 
inorganic food (CO,, H,0, NH,, N,OJ is lost. 



210 HOW CKOPS GROW. 

The following statement exhibits the Average Daily In- 
crease of Carbon, Hydrogen, Oxygen, Nitrogen, and Ash, 

(in lbs. per acre) during the several periods. 







Table X.- 


-Br. 








Carbon. 


Hydrogen. 


Oxygen. 


Nitrogen. 


Ash. 


1st Period, 


8.43 


1.13 


6.30 


0.65 


1.56 


8d " 


66.95 


8.94 


48.08 


3.30 


6.55 


4tU " 


23.84 


2.95 


24.06 


1.47 


1.44 


5tli " 


39.85 


3.89 


42.44 


1.04 


5.23 



Turning now to Arendt's results, which are carried more 
into detail than those of Bretschneider, we will notice 

A.— Tlie Relative {percentage) Composition of the 
Entire Plant and of its Parts * during the several periods 
of vegetation. 

!• Fiber \ is found in greatest relative quantity — 40° 1^ — 
in the lower joints of the stem, and from the time when 
the grain *' heads out," to the period of bloom. Relatively- 
considered, there occur great variations in the same part 
of the plant at different stages of growth. Thus, in the 
ear, which contains the least fiber, the quantity of this 
substance regularly diminishes, not absolutely, but only 
relatively, as the plant becomes older, sinking from 27° |o, 
at heading, to 12° |„, at maturity. In the leaves, which, as 
regards fiber, stand intermediate between the stem and 
ear, this substance ranges from 22°|o to 38°|q. Previous 
to blossom, the upper leaves, afterwards the lower leaves, 
are the richest in fiber. In the lower leaves the maximum. 



* Arendt selected large and well-developed plants, divided them into six parts, 
and analyzed each part separately. His divisions of the plants were 1, the three 
lowest joints of the stem ; 2, the two middle joints ; 3, the upper joint ; 4, the 
three lowest leaves ; 5, the two upper leaves ; 6, the ear. The stems were cut 
just ahove the nodes, the leaves included the sheaths, the ears were stripped from 
the stem. Arendt rejected all plants which were not perfect when gathered. 
When nearly ripe, the cereals, as is well known, often lose one or more of their 
lower leaves. For the numerous analyses on which these conclusions are based 
we must refer to the original. 

t i. e., Crude ceUvlose ; seep. 60. 



C0MP0SITI02«^ IN- SUCCESSIVE STAGES. 211 

(33° lo,) is found in the 4th; in the upper leaves, (38° |^,) in 
the 2d period. 

The apparent diminution in amount of fiber is due in 
all cases to increasevi production of other ingredients. 

2. Fat and Wax are least abundant in the stem. Their 
proportion increases, in general, in the upper parts of the 
stem, as well as in the later stages of its growth. The 
range is from 0.2° !„ to 3°!^. In the ear the proportion in- 
creases from 2°|o to 3.7° 1^. In the leaves the quantity is 
much larger and is mostly wax. The smallest proportion 
is 4.8° lo, which is found in the upper leaves, when the 
plant is ripe. The largest proportion, (10° 1^,) exists in 
the lower leaves, at the time of blossom. The relative 
quantities found in the leaves undergo considerable varia- 
tion from one stage of growth to another. 

3* JVbn-nitrogenous matters, other than fiber, — starch, 
sugar, etc.,* — undergo great and irregular variation. In 
the stem the largest percentage, (57° |„,) is found in the 
young lower joints; the smallest, (43°!^,) in ripe upper 
straw. Only in the ear occurs a regular increase, viz., 
from 54 to 63° |„. 

4. The Albuminoids, f in Arendt's investigation, exhibit 
a somewhat different relation to the vegetable substance, 
from what was observed by Bretschneider, as seen from 
the subjoined comparison of the percentages found at the 
different periods. 

Periods. 

J. II. III. IV. V. 

Arendt 20.93 11.65 10.86 13.67 14.30 

Bretschueider 23.73 17.67 17.61 15.39 

These differences may be variously accounted for. They 
are due, in part, to the fact that Arendt analyzed only 
large and perfect plants. Bretschneider, on the other 

* What remains after deducting fat and wax, albuminoids, fiber, and ash, 
from the dry substance, is here included. 

t Calculated by multiplying the percentage of nitrogen by 6.33. 



212 HOW CROPS GBOW. 

hand, examined all the plants of a giren plot, large and 
small, perfect and injured. The differences illustrate what 
has been already insisted on, viz., that the development 
of the plant is greatly modified by the circumstances of its 
growth, not only in reference to its external figure, but also 
as regards its chemical composition. 

The relative distribution of nitrogen in the parts of the 
plant at the end of the several periods is exhibited by the 
following table, simple inspection of which shows the fluc- 
tuations, (relative,) in the content of this element. The 
percentages are arranged for each period separately, pro- 
ceeding from the highest to the loAvest: 

PEKIOnS. 

I. II. III. IV. V. 

Upper leaves. Lower leaves. Upper leaves. Ears. Ears. 

3.74 2.39 2.27 2.85 3.04 

Lower leaves. Upper leaves. Lower leaves. Upper leaves. Upper leaves. 



3.38 


2.19 


2.18 


1.91 


1.74 


Lower leaves. 


Ears. 


Ears. 


Lower leaves. 


Upper stem. 


2.15 


2.06 


1.85 


1.62 


1.56 




Middle stem. 


Upper stem. 


Upper stem. 


Lower leaves. 




1.52 


1.34 


1.60 


1.43 




Upper stem. 


Middle stem. 


Middle stem. 


Middle stem. 




0.87 


0.98 


1.20 


1.17 




Lower stem. 


Lower stem. 


Lower stem. 


Lower stem. 




0.80 


0.88 


0.83 


0.79 



5t Ash. — The agreement of the percentages of ash in the 
entire plant, in corresponding periods of the growth of the 
oat, in the independent examinations of Bretschneider and 
Arendt is remarkably close, as appears from the figures 
below. 

PERIODS. ^ 
L II. III. IV. V. 

Bretschneider 8.57 5.98 5.33 5.40 

Areudt 8.03 5.24 5.44 5.20 5.17 

The diminution at the 2d, increase at the 3d, and sub- 
sequent diminution at the 4th period, are observed to run 
parallel in both cases. 

As regards the several parts of the plant, it was found 



COMPOSITION IN SUCCESSIVE STAGES. 213 

by Arendt that of the stem the upper portion was richest in 
ash throughout the whole period of growth. Of the leaves, 
on the contrary, the lower contained most fixed matters. 
In the ear there occurred a continual decrease from its 
first appearance to its maturity, while in the stem and 
leaves there was, in general, a progressive increase towards 
the time of ripening. Tiie greatest percentage, (10.5° |„,) 
was found in the ripe leaves; the smallest, (0.78° l^,) in the 
ripe lower straw. 

Far more interesting and instructive than the relative 
proportions are ^ 

B— The absolute quantities of the ingredients found 
in the plant at the conclusion of the several periods of 
growth* — These absolute quantities, as found by Arendt, 
in a given number of carefully selected and vigorous 
plants, do not accord with those obtained by Bretschhei- 
der from a given area of ground, nor could it be expected 
that they should, because it is next to impossible to cause 
the same amount of vegetation to develope on a number 
of distinct plots. 

Though the results of Bretschneider more nearly rep- 
resent the crop as obtained in farming, those of Arendt give 
a truer idea of the plant when situated in the best possible 
conditions, and attaining a uniformly high development. 
We shall not attempt to compare the two sets of observa- 
tions, since, strictly speaking, in most points they do not 
admit of comparison. 

From a knowledge of the absolute quantities of the sub- 
stances contained in the plant at the ends of several periods, 
we may at once estimate the rate of growth, i. e., the rapid- 
ity with which the constituents of the plant are either taken 
up or organized. 

The accompanying table, which gives in alternate col- 
umns the total weights of 1,0Q() plants at the end of the 
several periods, and, (by subtracting the first from the 



214 



HOW CROPS GROW. 



second, the second from the third, etc.,) the gain from 
matters absorbed or produced during each period, will 
serve to justify the deductions that follow, which are taken 
from the treatise of Arendt, and which apply, of course, 
only to the plants examined by this investigator. 
1,000 Entire Plants, (water-free.) 





Contain at 
end of and 
absorb or 
prochice 


ri 


ill 


n 






5.. 

IP 


■^ o 

fl 


^8s 




Period I. 

3 leaves 

open.* 


Period II. 

Heading 

out. 


Period III. 
Blossomed. 


Period IV. 
Beginning 
to ripen. 


Period V. 
Ripe. 


Fiber . 


103.3 
20.1 

201.4 
95.4 


459 7 


356 4 


564.8 
82.9 
916.7 
202.8 


105.1 
.34.0 

292.1 
43.9 


545.0 

97.6 

1242.6 

317.8 


Losfi 
14.7 
325.9 
115.0 


550.6 

89.8 

1340.0 

351.6 


Loss 


Fat [matters 

Other non - nitrogenous 


43.9 
624.6 
158.9 


28.8 
423.2 
63.5 


Loss 
97.4 
34.2 






Organic matter 


419.2 


1292.2 


873. 


1767.2 


475.1 


2203.0 


435.8 


2331.6 


128.6 



Silica 

Sulphuric acid... 
Phosphoric acid. 

Oxide of iron 

Lime 

Magnesia 

Chlorine 

Soda 

Potash 



6.39 
1.06 
3.27 
0.20 
4.48 
1.53 
2.28 



.60 



455.S 



15.82 
2.71 
5.99 
0.46 
8.50 
2.71 
3.62 
1.2S 

31.11 



70.03 



1363.6 



9.43 
1.65 
2.72 
0.26 
4.02 
1.18 
1.34 
0.42 
14.06 



33.43 



25.45 
2.63 

10.32 
0.61 

11.61) 
3.71 
5.32 
1.47 

40.20 



9.63 


4.33 
0.15 
3.10 
1.01 
1.70 
0.19 
9.09 



30.33 



34.66 
4 83 

12.90 
0.83 

14.49 
5.42 
5.96 
1.12 

44.33 



120. 



9.21 
2.12 
2.58 
0.22 
2.89 
1.71 
0.64 
Loss 
4.13 



20.34 



456.2 



36.32 
5.34 

14.23 
0.58 

14.71 
6.45 
5.78 
0.8T 

43.76 



126.93 



1.66 
0.41 
1.33 
Loss 
0.22 
1.03 
Loss 
Loss 
Loss 



18 



134.7 



Ash 

Dry Matter 

1. The plant increases in total weight, (dry matter,) 
through all its growth, but to unequal degrees in different 
periods. The greatest growth occurs at the time of head- 
ing out ; the slowest, within ten days of maturity. 

We may add that the increase of the oat after blossom 
takes place mostly in the seed, the other organs gaining 
but little. The lower leaves almost cease to grow after 
the 2d period. 

2. Mber is produced most largely at the time of head- 
ing out, (2d period.) When the plant has finished blos- 
soming, (end of 3d period,) the formation of fiber entirely 
ceases. Afterward there appears to occur a slight diminu- 



» The weights in this table are grams. One gram = 15.434 grains. As the 
weights have mostly a comparative value, redaction to the English standard is 
unnecessary 



COMPOSITION IN SUCCESSIVE STAGES. 215 

tion of this substance, probably due to unavoidable loss 
of lower leaves, but not to a resorption or metamorphosis 
in the plant. 

3* Mit is formed most largely at the time of blossom. It 
ceases to be produced some weeks before ripening. 

4. The formation of Albuminoids is irregular. The 
greatest amount is organized during the 4th period, (after 
blossoming.) The gain in albuminoids within this period 
is two-fifths of the total amount found in the ripe plant, 
and also is nearly two-fifths of the entire gain of organic 
substance in the same period. The absolute amount or- 
ganized in the 1st period is not much less than in the 4th, 
but in the 2d, 3d, and 5th periods, the quantities are con- 
siderably smaller. 

Bretschneider gives the data for comparing the produc- 
tion of albuminoids in the oat crop examined by him with 
Arendt's results. Taking the quantity found at the con- 
clusion of the 1st peiiod as 100, the amounts gained during 
the subsequent periods are related as follows : 

PERIODS. 

I. IL III. (II & III.) IV. (II, III & IV.) V. 

Arendt 100 67 46 (113) 120 (233) 36 

Bretschneider... 100 *? ? (165) 62 (227) 35 

We perceive striking differences in the comparison. In 
Bretschneider's crop, the increase of albuminoids goes on 
most rapidly in the 3d period, and sinks rapidly during 
the time when in Arendt's plants it attained the maximum. 
Curiously enough, the gain in the 2d, 3d, and 4th periods, 
taken together, is in both cases as good as identical, (233 
and 227,) and the gain during the last period is also equal. 
This coincidence is doubtless, however, merely accidental. 
Comparisons with other crops of oats,examined,though very 
incompletely, by Stockhardt, {Chemischer AcJcersmann, 
1855,) and Wolff, {Die Erschopfung des Bodens durch die 
Cidtur^ 1856,) demonstrate that the rate of assimilation is 
not related to any special times or periods of development^ 



216 HOW CEOPS GEOW. 

hut depends upon the stores of food accessible to the plant 
and the favorahleness of the iceather to growth. 

The following figures, which exhibit for each period of 
both crops a comparison of the gain in albuminoids with 
the increase of the other organic matters, further demon- 
strate that in the act of organization, tlie nitrogenous prin- 
ciples have no close quantitative relations to the non-ni- 
trogenous bodies, (amyloids and fats.) 

The quantities of albuminoids gained during each period 
being represented by 10, the amounts of amyloids, etc., 
are seen from the subjoined ratios : 

PERIODS. 

Hatio in 
I. II & III. IV. V. EipeBant. 

Arendt 10:34 10:114 10:28 10: 25 10:66 

Bi-etsclineider..lO : 30 10 : 50 10 : 46 10 : 120 10 : 51 

5* The Ash-ingredients of the oat are absorbed through- 
out its entire growth, but in regularly diminishing quan- 
tity. The gain during the 1st period being 10, that in the 
2d period is 9, in the 3d, 8, in the 4th, 5^, in the 5th, 2 
nearly. 

The ratios of gain in ash-ingredients to that in entire 
dry substance, are as follows, ash-ingredients being as- 
sumed as 1, in the successive periods : 

1 : 121 1 : 27, 1 : 16, 1 : 23, 1 : 19. 
Accordingly, the absorption of ash-ingredients is not pro- 
portional to the growth of the plant, but is to some degree 
accidental, and independent of the wants of vegetation. 

Recapitulation. — Assuming the quantity of each proxi- 
mate element in the ripe plant as 100, it contained at the 
end of the several periods the following amounts : 





Fiber. 


Fat. 


Amyloids. 


Allmminoids. 


Ash 


I. Period, 


18° lo 


20a lo 


■ 150 lo 


270 lo 


290 


II. " 


81" 


50 " 


47" 


45" 


55 


III. " 


100" 


85" 


70" 


57" 


79 


IV. " 


100" 


100" 


92" 


90" 


95 


V. " 


100" 


100" 


100" 


100" 


100 



COMPOSITION" IN SUCCESSIVE STAGES. 217 



The gain 


during each period 


was accordingly as fol- 


lows: 










Fiber. Fat. Amyloids. 


Albuminoids. Ash. 


I. Period, 


180 lo 200 lo 


150 lo 


270] 290 lo 


II. " 


63 " 30 " 


32" 


18 " 26 " 


III. " 


19 " 35 " 


23" 


12 " 24 " 


IV. " 


" 15 " 


22" 


33 " 16 " 


V. " 


" " 


8^' 


10 " 5 " 



100 " 100 " 100 " 100 " 100 " 

6i — As regards the individual ingredients of the ash, 
the plant contained at the end of each period the follow- 
ing amounts, — the total quantity in the ripe plant being 
taken at 100. Corresponding results from Bretschneider 
enclosed in ( ) are given for comparison. 



Silica. 


Sulphuric 
Acid. 


Phosphoric 
Acid. 


Lime. 


Magnesia. 


Potash. 


Per cent. 


Per cent. 


Per cent. 


Per cent. 


Per cent. 


Per cent. 


38 ( 22) 

93 (72) 
100 (100) 


20 (42) 


23 ( 23) 


30 (31) 
?^((83) 


24 ( 31) 
ii(^3) 


39 ( 42) 


90 ( 39) 
100 (100) 


91 ( 74) 
100 (100) 


99 (74) 
100 (100) 


84 ( 77) 
100 (100) 


100 (100) 
100 (95*) 



I. Period, 
II. " 

III. " 

IV. " 
V. " 

The gai?i (or loss, indicated by the minus sign — ) in 
these ash-ingredients during each period is given below. 

Silica. '^"tc?r''' ^^"^Acid!'" ^^^- ^cignesia. Potash. 

Percent. Percent. Percent. Percent. Percent. Percent. 

I. Period, 18 ( 22) 20 ( 42 ) 23 ( 23) 30 ( 31 ) 24 ( 31) 39 ( 42 ) 

& " 11(33) »^J(2, "5(40) i}(=2, gj(«, |}}(4-) 

IV. " 23 ( 15) 38 (-5*) 18 ( 10) 20 (-9*) 26 ( 4 ) 9 ( 11 ) 

V. " 7 ( 28) 10 ( 56 ) 9 ( 27) 1 ( 17 ) 16 ( 23) (—5*) 

100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 

These two independent investigations could hardly give 
all the discor(3ant results observed on comparing the above 
figures, as the simple consequence of the unlike mode of 
conducting, them. We observe, for example, that in the 
,last period Arendt's plants gathered less silica than in any 
other — only T\^ of the whole. On the other hand, Bret- 
schneider's crop gained more silica in this than in any 

* IntheseiustancesBretschneider's later crops contained less sulphuric acid, lime, 
and potash, than the earlier. This result may he due to the washing of the crop by 
rains, but is probably caused by unequal development of the several plots. 

10 



218 HOW CROPS GEOW. 

Other single period, viz. : 28° l^. A similar statement is 
true of phosphoric acid. It is obvious that Bretschnei- 
der's crop was taking up fixed matters much more vigor- 
ously in its last stages of growth, than were Arendt's 
plants. As to potash we observe that its accumulation 
ceased in the 4th period in both cases. 

It is, on the whole, plain that we cannot safely draw from 
these interesting researches any very definite conclusions 
as to the rate and progress of assimilation and growth in 
the oat plant, beyond what have been already pointed out. 

C— Translocation of substances in the Plant.— The 
translocation of certain matters from one part of the plant 
to another is revealed by the analyses of Arendt, and 
since such changes are of interest from a physiological 
point of view, we may recount them here briefly. 

It has been mentioned already that the growth of the 
stem, leaves, and ear, of the oat plant in its later stages 
probably takes place to a great degree at the expense of 
the roots. It is also probable that a transfer of amyloids, 
and certain that one of albuininoids, goes on from the 
leaves through the stem into the ear. 

Silica appears not to be subject to any change of posi- 
tion after it has once been fixed by the plant. Chlorine 
likewise reveals no noticeable mobility. 

On the other hand phosphoric acid passes rapidly from 
the leaves and stem towards or into the fruit in the earlier 
as well as in the later stages of growth, as shown by the 
following figures : 

1,000 plants contained in the various periods, quantities 
(grams) of phosphoric acid as follows : 

1st Period. M Period. M Period, ^th Period. Uh Period. 



3 lower joints of stem 


0.47 


0.20 


0.21 


0.20 


0.19 


2 middle *' " 





0.39 


1.14 


0.46 


0.18 


Upper joint 


— 


0.66 


1.73 


0.31 


0.39 


3 lower leaves " 


1.05 


0.70 


0.69 


0.51 


0.35 


2 upper leaves " 


1.75 


1.67 


1.18 


0.74 


0.59 


Ear 


— 


2.36 


5.36 


10.67 


12.53 



COMPOSITTOK IN- SUCCESSIVE STAGES. 219 

Observe that these absolute quantities diminish in the 
stem and leaves after the 1st or 3d period in all cases, and 
increase very rapidly in the ear. 

Arendt found that sulphuric acid existed to a much 
greater degree in the leaves than in the stem, throughout 
the entire growth of the oat plant, and that after blos- 
soming the lower stem no longer contained sulphur in the 
form of sulphuric acid at all, though its total in the plant 
considerably increased. It is almost certain, then, that 
sulphuric acid originates^ either partially or wholly, by 
oxidation of sulphur or some sulphurized compound, in 
the upper organs of the oat. 

Magnesia is translated from the lower stem into the 
upper organs, and in the fruit, especially, it constantly in- 
creases in quantity. 

There is no evidence that lime moves upward in the 
plant. On the contrary, Arendt' s analyses go to show 
that in the ear during the last period of growth, it dimin- 
ishes in quantity, being, perhaps, replaced by magnesia. 

As to potash^ no transfer is fairly indicated except from 
the ears. These contained at blossoming (period III) a 
maximum of potash. During their subsequent growth 
the amount of potash diminished, being probably displac- 
ed by magnesia. 

The data furnished by Arendt's analyses, while they in- 
dicate a transfer of matters in the cases just named and in 
most of them with great certainty, do not and cannot from 
their nature disprove the fact of other similar changes, and 
cannot fix the real limits of the movements which they 
point out. 



DIVISION II. 

THE STRUCTURE OF THE PLANT AND 
OFFICES OF ITS ORGANS. 

CHAPTER L 

GENEEALITIES. 

'■ We have given a brief description of those elements 
and compounds which constitute the plant in a chemical 
sense. They are the materials — the stones and timbers, so 
to speak — out of which the vegetable edifice is built. It 
is important in the next place to learn how these building 
materials are put together, what positions they occupy, 
what purposes they serve, and on what plan the edifice is 
constructed. 

It is impossible for the builder to do his work until he 
has mastered the plans and specifications of the architect. 
So it is hardly possible for the farmer with certainty to 
contribute in any great, especially in any new degree, to 
the upbuilding of the jDlant, unless he is acquainted with 
the mode of its structure and the elements that form it. 
It is the happy province of science to add, to the vague and 
general information which the observation and experience 
of generations has taught, a more definite and particular 
knowledge, — a knowledge acquired by study purposely 
and carefully directed to special ends. 

An acquaintance with the parts and structure of the plant 
is indispensable for understanding the mode by which 
220 



ORGANS OF THE PLAINT. 221 

it derives its food from external sources, while the ingen- 
ious methods of propagation practiced in fruit and flower 
culture are only intelligible by the help of this knowledge. 

Organism of the Plant. — We have at the outset 
.spoken of organic matter, of organs and organization. 
It is in the world of life that these terms have their fittest 
application. The vegetable and animal consist of numer- 
ous parts, differing greatly from each other, but each essen- 
tial to the whole. The root, stem, leaf, flower, and seed, 
are each instruments or organs whose co-operation is need- 
ful to the perfection of the plant. The plant (or animal), 
being thus an assemblage of organs, is called an Organism; 
it is an Organized or Organic Structure. The atmos- 
phere, the waters, the rocks and soils of the earth, are 
mineral matters ; they are inorganic and lifeless. 

In inorganic nature, chemical affinity rules over the 
transformations of matter. A plant or animal that is 
dead, under ordinary circumstances, soon loses its form and 
characters ; it is gradually consumed by the atmospheric 
oxygen, and virtually burned up to air and ashes. 

In the organic world a something, which we call the 
Vital Principle^ resists and overcomes or modifies the af- 
finities of oxygen, and ensures the existence of a con- 
tinuous and perpetual succession of living forms. 

The organized structure is characterized and distinguish- 
ed from mineral matter by two particulars : 

1. It builds up and increases its own mass by appropri- 
ating external matter. It assimilates surrounding sub- 
stances. It groios by the absorption of food. 

2. It reproduces itself. It comes from, and forms again 
a seed or germ. 

Ultimate and Complex Organs. — ^In our account of 
the Structure of the Plant we shall first consider the ele- 
ments of that structure — the Primary Organs or Vegetable 
Cells — which cannot be divided or wounded without ex- 



222 HOW CROPS GEOW. 

tinguishing their life, and by whose expansion or multipli- 
cation all growth takes place. Then will follow an account 
of the complex parts of the plant — its Compound Organs 
— which are built up by the juxtaposition of numerous 
cells. Of these we have one class, viz. : the Roots, Stems, 
and Leaves, whose office is to sustain and nourish the Indi- 
vidual Plant. These may be distinguished as the Vege- 
tative Organs. The other class, comprising the Flower 
and. Fruit, are not essential to the existence of the individ- 
ual, but their function is to maintain the Race. They are 
the Meproductive Organs, 



CHAPTER n. 
THE PRIMARY ELEMENTS OF ORGANIC STRUCTURE. 

§1. 

THE VEGETABLE CELL. 

One of the most interesting discoveries that the micro- 
scope has revealed, is, that all organized matter originates 
in the form of minute vesicles or cells. If we examine by 
the microscope a seed or an Qgg^ we find nothing but a 
cell-structure — an assemblage of little globular bags or 
vesicles, lying closely together, and more or less filled 
with solid or liquid matters. From these cells, then, comes 
the frame or structure of the plant, or of the animal. In 
the process of maturing, the original vesicles are often 
greatly modified in shape and appearance, to suit various 
purposes; but still, it is always easy, especially in the 
plant, to find cells of the same essential characters as those 
occurrino: in the seed. 




ELEMENTS OF ORGANIC STRUCTUEE. 223 

Cellular Plants. — In those classes of vegetation which 
depart structurally to the least degree from the seed, and 
which belong to what are called the " lower orders,"* we 
find plants which consist entirely of cells throughout 
all the stages of their life, and indeed many are known 
which are but a single cell. The phenomenon of red snow, 
frequently observed in Alpine and Arctic regions, is due to 
a microscopic one-celled plant which propagates with great 
rapidity, and gives its color to the 
surface of the snow. In the chem- 
ist's laboratory it is often observed 
^ ^ that, in the clearest solutions of 

^ ^ salts, like the sulphates of soda and 

Fig. 27. magnesia, a flocculent mould, some- 

times red, sometimes green, most often white, is formed, 
which, under the microscope, is seen to be a vegetation 
consisting of single cells. Brewer's yeast, fig. 27, is nothing 
more than a mass of one or few-celled plants. 

In the mushrooms and sea- weeds, as well as in the moulds 
that grow on damp walls, or upon bread, cheese, etc., and 
in the brand or blight which infests many of the farmer's 
crops, we have examples of plants formed exclusively of 
cells. 

All the plants of higher orders we find likewise to coi> 
sist chiefly of globular or angular cells. 
All the growing parts especially, as the 
tips of the roots, the leaves, flowers, and 
fruit, are, for the most part, aggregations 
of such minute vesicles. 

If we examine the pulp of fruits, as that |^\ 
of a ripe apple or tomato, we are able, by ^ 
means of a low magnifier, to distinguish 
the cells of which it almost entirely con- ^^o" ^^• 

sists. Fig. 28 represents^ bit of the flesh of a ripe pippin, 

* Viz. : the Cryptogams^ including Moulds, and Mushrooms, {Fungi,) Mosses, 
Ferns, and Sea- Weeds, (Algce). 





224 HOW CROPS GEOW. 

magnified 50 diameters. The cells mostly cohere together, 
but readily admit of separation. 

Structure of the Cell. — ^By the aid of the microscope 
it is possible to learn something with regard to the inter- 
nal structure of the cell itself Fig. 29 exhibits the ap- 
pearance of a cell from the flesh of the Jerusalem Arti- 
choke, magnified 230 diameters ; externally the membrane, 
or Avail of the cell, is seen in section. This membrane is 
filled and distended by a transparent 
liquid, the sap or free water of vegetation. 
Within the cell is observed a round body, 
-& Z>, which is called the nucleus^ and upon 
this is seen a smaller nucleolus^ c. Lining 
the interior of the cell-membrane and 
connected with the nucleus, is a yellowish, 
turbid, semi-fluid substance of mucilagi- 
Fig. 29. nous consistence, a, which is designated 

the protoplasm,^ or formative layer. This, when more 
highly magnified, is found to contain a vast number of 
excessively minute granules. 

By the aid of chemistry the microscopist is able to dis- 
sect these cells, which are hardly perceptible to the unas- 
sisted eye, and ascertain to a good degree how they are 
constituted. On moistening them with solution of iodine, 
and afterward with sulphuric acid, the outer membrane — 
the cell-wall — shortly becomes of a fine blue color. It is 
accordingly cellulose, the only vegetable substance yet 
known which is made blue by iodine after, and only after, 
the action of sulphuric acid. At the same time we observe 
that the interior, half-liquid, protoplasm, has congulated 
and shrunk together, — has therefore separated from the 
cell-wall, and including with it the nucleus and the smaller 
granules, lies in the center of the cell like a collapsed 
bladder. It has also assumed a deep yellow or brown 
color. If we moisten one of these cells with nitric acid, 
the cell-wall is not affected, but the liqnid penetrates it, 



ELEMENTS OF ORGANIC STRUCTUEE. 225 

coagulates the inner membrane, and colors it yellow. 
In the same way this membrane is tinged violet-blue 
by chlorhydric acid. These reactions leave no room 
to doubt that the slimy inner lining of the cell is chiefly 
an albuminoid. It has been termed by vegetable physiol- 
ogists the protoplasm or formative layer^ from the fact 
that it is the portion of the cell first formed, and that from 
which the other parts are developed. The protoplasm is 
not miscible with or soluble in water. It is contractile, 
and in the living cell is constantly changing its figure, 
while the granules commonly suspended iia it move and 
circulate as in a stream of liquid. 

If we examine the cells of any other plant we find al- 
most invariably the same structure as above described, 
provided the cells are young, i. e., belong to growing 
parts. In some cases cells consist only of protoplasm and 
nucleus, being destitute of cell-walls during a portion or 
the whole of their existence. 

In studying many of the maturer parts of plants, viz. : 
such as have ceased to enlarge, as the full-sized leaf, the 
perfectly formed wood, etc., we find the cells do not cor- 
respond to the description just given. In external shape, 
thickness, and appearance of the cell-wall, and especially 
in the character of the contents, there is indefinite variety. 
But this is the result of change in the original cells, which, 
so far as our observations extend, are always, at first, 
formed closely on the pattern that has been explained. 

Vegetable Tissue. — ^It does not, however, usually hap- 
pen that the individual cells of the higher orders of j^lants 
admit of being obtained separately. They are attached 
together more or less firraly by their outer surfaces, so as 
to form a coherent mass of cells — a tissue^ as it is termed. 
In the accompanying cut, fig. 30, is shown a highly 
magnified view of a portion of a very thin slice across a 
young cabbage stalk. It exhibits the outline of the ir- 
10* 



226 



HOW CROPS GROW. 




Fig. 80. 



regular empty cells, the walls of which are, for the most 
part, externally united and appear as one, a. At the points 
indicated by 5, cavities between the cells are seen, called 
intercellular spaces. A slice across the potato-tuber, (see 
fig. 52, p. 277,) has a similar appearance, except that the 

cells are filled with starch, 
and it would be scarcely 
possible to dissect them 
apart; but when a pota- 
to is boiled, the starch- 
grains swell, and the cells, 
in consequence, separate 
from each other, a practi- 
cal result of which is to 
make the potato mealy. 
A thin slice of vegetable 
ivory (the seed of ^Ay- 
telephas macrocarpa), 
under the microscope, dry or moistened with water, pre- 
sents no trace of cell-structure, the cells being united as 
one ; however, upon soaking in sulphuric acid, the mass 
softens and swells, and the individual cells are at once 
revealed, their surfaces separating in six-sided outlines. 

Form of Cells. — In the soft, succulent parts of plants, 
the cells lie loosely together, often w^ith considerable inter- 
cellular spaces, and have mostly a rounded outline. In 
denser tissues, the cells are crowded together in the least 
possible space, and hence often appear six-sided when seen 
in cross-section, or twelve-sided if viewed entire. A piece 
of honey-comb is an excellent illustration of the appear- 
ance of many forms of vegetable cell-tissue. 

The pulp of an orange is the most evident example of 
cell-tissue. The individual cells of the ripe orange may 
be easily separated from each other, as they are one-fourth 
of an inch or more in length. Being mature and incapa- 
ble of further growth, they possess neither protoplasm nor 



ELEMENTS OF ORGANIC STRUCTUEE. 



227 



nucleus, but are filled with a sap or juice containing citric 

acid and sugar. 

In the pith of the rush, star-shaped cells are found. In 
common mould the cells are long and 
thread-like. In the so-called frog-spittle 
they are cylindrical and attached end to 
end. In the bark of many trees, in the 
stems and leaves of grasses, they are 
square or rectangular. 

Cotton-fiber, flax and hemp consist of 
long and slender cells, fig. 31. Wood is 
mostly made up of elongated cells, tapered 
at the ends and adhering together by 
their sides. Fig. 49, c. A., p. 271. 

Each cotton- fiber is a single cell which forms an 
external appendage to the seed-vessel of the cot- 
ton plant. When it has lost its free water of 
vegetation and become air-dry, its sides collapse 
and it resembles a twisted strap. J., in fig. 31, 
exhibits a portion of a cotton-fiber highly magnified. 
The flax-fiber, from the inner bark of the flax- 
^^" • stem, &, fig. 31, is a tube of thicker walls and 

smaller bore than the cotton-fiber, and hence is more durable than cot- 
ton. It is very flexible, and even when crushed or bent short, retains 
much of its original tenacity. Hemp-fiber closely resembles flax-fiber in 
appearance. 

Xliickening; of tlxe> Cell-]fleni1>rane. — The growth of the 
cell, which, when young, always has 
a very delicate outer membrane, often 
results in the thickening of its walls 
by the interior deposition of cellu- 
lose and lignin. This thickening may 
take place regularly and uniform- 
ly, or interruptedly. The flax-fiber, 
&, fig. 31, is an example of nearly 
uniform thickening. The irregular 
deposition of cellulose is shown in 
fig. 33, which exhibits a section from 
the seeds (cotyledons) of the com- 
mon nasturtium, ( Tropceolxhm majus). The original membrane is coated 
interiorly with several distinct and successively-formed linings, which 
are hot continuous, but are irregularly developed. Seen in section, the 





Fig. 33. 



228 HOW CROPS GKOW. 

thickening has a waved outline, and at points, the original cell-mem- 
brane is hare. Were these cells viewed entire, we should see at these 
points, on the exterior of the cell, dots or circles appearing like orifices, 
but being simply the unthickened portions of the cell-wall. The cells 
in fig. 32 exhibit each a central nucleus surrounded by grains of aleurone. 

Cell ContentSi — Besides the protoplasm and nucleus, 
the cell usually contains a variety of bodies, which have 
been, indeed, noticed already as ingredients of the plant, 
but which may be here recapitulated. Many cells are al- 
together empty, and consist of nothing but the cell-wall. 
Such are found in the bark or epidermis of most plants, 
and often in the pith, and although they remain connected 
with the actually Hving parts, they have no proper life in 
themselves. 

All living or active cells are distended with liquid. This 
consists of water, which holds in solution gum, dextrin, 
inulin, the sugars, organic acids, and other less important 
vegetable principles, together with various salts, and 
constitutes the sap of the plant. In oil-plants, droplets of 
oil occupy ceitiiin cells, fig. 17, p. 90 ; while in numerous 
kinds of vegetation, colored and milky juices are found in 
certain spaces or channels between the cells. 

The w^ater of the cell comes from the soil, as we shall 
hereafter see. The matters, which are dissolved in the sap 
or juices of the plant, together wdth the semi-solid proto- 
plasm, undergo transformations resulting in the production 
of solid substances. By observing the various parts of a 
plant at the successive stages of its development, under 
the microscope, we are able to trace within the cells the 
formation and growth of starch-grains, of crystalloid and 
granular bodies consisting chiefly of vegetable casein, and 
of the various matters w^hich give color to leaves and 
flowers. 

The circumstances under ^vhich a cell developes deter- 
mine the character of its contents, according to laws that 
are hidden from our knowledge. The outer cells of the 
potato-tuber are incrusted with corky matter, the inner 



ELEMENTS OF ORGANIC STRUCTUEE. 229 

ones, most of them, are occupied entirely with starch, fig. 
52, p. 277. In oats, wheat, and other cereals, we find, just 
within the empty cells of the skin or epidermis of the 
grain, a few layers of cells that contain scarcely anything 
but albuminoids, with a little fat ; while the interior cells 
are chiefly filled with starch ; fig. 18, p. 106. 

Transformations in Cell Contents. — The same cell may 
exhibit a great variety of aspect and contents at different 
periods of growth. This is especially to be observed in 
the seed while developing on the mother plant. Hartig 
has traced these changes in numerous plants under the mi- 
croscope. According to this observer, the cell-contents of 
the seed (cotyledons) of the common nasturtium, {Trop- 
ceohim majus,) run through the following metamorphoses. 
Up to a certain stage in its development the interior of 
the cells are nearly devoid of recognizable solid matters, 
other than the nucleus and the adhering protoplasm. 
Shortly, as the growth of the seed advances, green grains 
of chlorophyll make their appearance upon the nucleus, 
completely covering it from view. At a later stage, these 
grains, which have enlarged and multiplied, are seen to 
have mostly become detached from the nucleus, and lie 
near to and in contact with the cell-wall. Again, in a 
short time the grains have lost their green color and have 
assumed, both as regards appearance and deportment with 
iodine, all the characters of starch. Subsequently, as the 
seed hardens and becomes firmer in its tissues, the micro- 
scope reveals that the starch-grains, which were situated 
near the cell-wall, have vanished, while the cell-wall itself 
has thickened inwardly — the starch having been convert- 
ed into cellulose. Again, later, the nucleus, about which, 
in the meantime, more starch-grains have been formed, 
undergoes a change and disappears ; then the starch-grains, 
some of which have enlarged while others have vanished, 
are found to be imbedded in a pasty matter, which has the 
reactions of an albuminoid. From this time on, the 



230 



HOW CROPS GROW. 



starch-grains are gradually converted from their surfaces 
inwardly into smaller grains of aleurone, which, finally, 
when the seed is mature, completely occupy the cells. 

In the sprouting of the seed similar changes occur, but 
in reversed order. The nucleus reappears, the aleurone dis- 
solves, and even the cellulose stratified upon the interior 
of the cell, fig. 32, wastes away and is converted into 
soluble food (sugar ?) for the seedling. 

The Dimensions of Veg^etable Cells are very various. 
A creeping marine plant is known — the Caulerpa proUfera, 




Fig. 33. 

fig. 33, — which consists of a single cell, though it is often 
a foot in length, and is branched with what have the ap- 
pearance of leaves and roots. The pulp of the orange con- 
sists of cells which are one-quarter of an inch or more in 
diameter. Every fiber of cotton is a single cell. In most 



ELEMENTS OF ORGANIC STRUCTURE. 



231 



cases, however, the cells of plants are so small as to re- 
quire a powerful microscope to distinguish them, — are, in 
fact, no more than l-1200th to l-200th of an inch in diam- 
eter ; many are vastly smaller. 

Growth. — The growth of a plant is nothing more than 
the aggregate result of the enlargement and multiplication 
of the cells which compose it. In most cases the cells at- 
tain their full size in a short time. The continuous growth 
of plants depends, then, chiefly on the constant and rapid 
formation of new cells. 

€elI-multiplication« — The young and active cell always 
contains a nucleus, (fig. 34, h.) Such a cell may produce 
a new cell by division. In this process 
the nucleus, from which all cell-growth 
appears to originate, is observed to re- 
-Tf solve itself into two parts, then the 
protoplasm, a, begins to contract or in- 
fold across the cell in a line correspond- 
in «■ with the division of the nucleus, until 
the opposite infolded edges meet — like 
the skin of a sausage where a string is 
tightly tied around it, — thus separating the two nuclei and 
inclosing each within its new cell, which is completed by 
a further external growth of cellulose. 

In one-celled plants, like yeast, (fig. 35,) the new cells 
thus formed, bud out from the side 
of the parent-cell, and before they 
obtain full size become entirely 
detached from it, or, as in higher 
plants, the new cells remain adher- 
ing to the old, forming a tissue. 

In free cell-formation nuclei are observed to develope 
in the protoplasm of a parent cell, which enlarge, surround 
themselves with their own protoplasm and cell-membrane, 
and by the resorption or death of the parent cell become 
independent of the latter* 





Fis:. 35. 



232 HOW CROPS GROW. 

The rapidity with which the vegetable cells may multi- 
ply and grow is illustrated by many familiar facts. The 
most striking cases of quick growth are met with in the 
mushroom family. Many will recollect having seen on the 
morning of a June day, huge puff-balls, some as large as a 
peck measure, on the surface of a moist meadow, where 
the day before nothing of the kind was noticed. In such 
sudden growth it has been estimated that the cells are 
produced at the rate of three or four hundred millions per 
hour. 

Permeability of Cells to Liquids,— Although the high- 
est magnifying power that can be brought to bear upon 
the membranes of the vegetable cell fails to reveal any 
apertures in them, — they being, so far as the best-assisted 
vision is concerned, completely continuous and imperforate, 
— they are nevertheless readily permeable to liquids. 
This fact may be elegantly shown by placing a delicate 
slice from a jDotato-tuber, immersed in water, under the 
microscope, and then bringing a drop of solution of iodine 
in contact with it. Instantly this reagent penetrates the 
walls of the unbroken cells without perceptibly affecting 
their appearance, and being absorbed by the starch-grains, 
at once colors them intensely purplish-blue. The particles 
of which the cell-walls and their contents are composed, 
must be separated from each other by distances greater 
than the diameter of the particles of water or of other 
liquid matters which thus permeate the cells. 

THE VEGETABLE TISSUES. 

As already stated, the cells of the higher kinds of plants 
are united together more or less firmly, and thus consti- 
tute what are known as Vegetable Tissues. Of these, 
a large number have been distinguished by vegetable anat- 



ELISMENTS OF ORGANIC STRUCTURE. 238 

omists, the distinctions being based either on peculiarities 
of form or of function. For our purposes it will be neces- 
sary to define but a few varieties, viz., Cellular Tissue, 
Woody Tissue, Bast-Tissue, and Vascular Tissue. 

Cellular or Cell-Tissue is the simplest of all, being 
a mere aggregation of globular or polyhedral cells whose 
walls are in close adhesion, and whose juices commingle 
more or less in virtue of this connection. Cellular tissue 
is the groundwork of all vegetable structure, being the 
only form of tissue in the simpler kinds of plants, and 
that out of which all the others are developed. The 
term parenchyma is synonymous with cell-tissue. 

Wood-Tissue, in its simplest form, consists of cells that 
are several or many times as long as they are broad, and 
that taper at each end to a point. These spindle-shaped 
cells cohere firmly together by their sides, and " break 
joints " by overlapping each other, in thfs way forming 
the tough fibers of wood. Wood-cells are often more 
or less thickened in their walls by depositions of cellulose, 
lignin, and coloring matters, according to their age and 
position, and are sometimes dotted and perforated, as will 
be explained hereafter, fig. 53, p. 278. 

Bast-TisS^ue is made up of long and slender cells, similar 
to those of wood-tissue, but commonly more delicate and 
flexible. The name is derived from the occurrence of this 
tissue in the bast, or inner bark. Linen, hemp, and all 
textile materials of vegetable origin, cotton excepted, con- 
sist of bast-fibers. Bast-cells occupy a place in rind, corres- 
ponding to that held by wood-cells in the interior of the 
stem, fig. 49, p. 271 . Prosenchyma is a name applied to 
all tissues composed of elongated cells, like those of wood 
and bast. Parenchyma and prosenchyma insensibly shade 
into each other. 

Vascular Tissue is the term applied to those unbranched 
Tubes and. Ducts which are found in all the higher orders 



234 HOW CROPS GEOW. 

of plants, interpenetrating the cellular tissue. There are 
several varieties of ducts, viz., dotted ducts^ ringed or an- 
nular ducts, and spiral ducts, of which illustrations will 
be given when the minute structure of the stem comes 
under notice, fig. 49, p. 271. 

The formation of vascular tissue takes place by a simple 
alteration in cellular tissue. A longitudinal series of ad- 
hering cells represents a tube, save that the bore is ob- 
structed with numerous transverse partitions. By the 
removal or perforation of these partitions a tube is devel- 
oped. This removal or perforation actually takes place 
in the living plant by a process of absorption. 



CHAPTER III 
THE VEGETATIVE ORGANS OF PLANTS. 

§1. 
THE ROOT. 

The Roots of plants, with few exceptions, from the first 
moment of their development grow downward, in obe- 
dience to" the force of gravitation. In general, they require 
a moist medium. They will form in water or in moist cot- 
ton, and in many cases originate from branches, or even 
leaves, when these parts of the plant are buried in the 
earth or immersed in water. It cannot be assumed that 
they seek to avoid the light, because they may attain a 
full development without being kept in darkness. The 



THE VEGETATIVE ORGANS OF PLANTS. 235 

action of light upon them, however, appears to be unfavor- 
able to their functions. 

The Growth of Roots occurs mostly by lengthening, 
and very little or very slowly by increase of thickness. 
The lengthening is chiefly manifested toward the outer 
extremities of the roots, as was neatly demonstrated by 
Wigand, who divided the young root of a sprouted pea ' 
into four equal parts by ink-marks. After three days, the 
first two divisions next the seed had scarcely lengthened 
at all, while the third was double, and the fourth eight 
times its previous length. Ohlerts made j^recisely similar 
observations on the roots of various kinds of plants. The 
growth is confined to a space of about ^|g of an inch from 
the tip. (Zinnea, 1837, pp. 609-631.) This peculiarity, 
adapts the roots to extend through the soil in all direc- 
tions, and to occupy its smallest pores, or rifts. It is 
likewise the reason that a root, which has been cut oif in 
transplanting or otherwise, never afterwards extends in 
length. 

Although the older parts of the roots of trees and of 
the so-called root-crops acquire a considerable diameter, 
the roots by which a plant feeds are usually thread-like 
and often exceedingly slender. 

SpongioleSt — The tips of the rootlets have been termed 
spongioles, or spongelets, from the idea that their texture 
adapts them especially to collect food for the plant, and 
that the absorption of matters from the soil goes on exclu- 
sively through them. In this sense, spongioles do not 
exist. The real living apex of the root is not, in fact, the 
outmost extremity, but is situated a little within that 
point. 

Root-Cap. — The extreme end of the root usually consists 
of cells that have become loosened and in part detached 
from the proper cell-tissue of the root, which, therefore, 
shortly perish, and serve merely as an elastic cushion or 



236 



HOW CROPS GROW. 



cap to protect the true termination or living point of the 
root in its act of penetrating the soil. Fig. 36 represents 
a magnified section of part of a 
barley root, showing the loose 
cells which slough off from the tip. 
These cells are filled with air in- 
stead of sap. 
A most strik- 
ing illustra- 
tion of the 
root - cap is 
furnished by 
the air-roots 
of the so- 
called Screw 
'Piue,{Panda- 
nvs odoratis- 




Fior. 36. 



simus,) exhibited in natural dimen- 
sions, in fig. 37. These air-roots issue 
from the stem above the ground, and, 
growing downwards, enter the soil, 
and become roots in the ordinary sense. 
When fresh, the diameter of the 
root is quite uniform, but the parts 
above the root-cap shrink on drying, 
while the I'oot-cap itself retains nearly 
its original dimensions, and thus 
reveals its different structure. 

Distinction between Root and 
Stem* — N^ot all the subterranean parts 
of the plant are roots in a proper Fig. 37. 

sense, although commonly spoken of as such. The tubers 
of the potato and artichoke, and the fleshy horizontal parts 
of the sweet-flag and pepper-root, are merely underground 
stems, of which many varieties exist. 

These and all other stems are easily distinguished from 




THE VEGETATIVE OEGANS OF PLANTS. 23T 

true roots by tlie imbricated huds^ of which indications 
may usually be found on their surfaces, e. g.^ the eyes of 
the potato-tuber. The side or secondary roots are indeed 
marked in their earliest stages by a protuberance on the 
primary root, but these have nothing in common with the 
structure of true buds. The onion-bulb is itself a fleshy 
bud, as will be noticed subsequently. The true roots of 
the onion are the libers which issue from the base of the 
bulb. The roots of many plants exhibit no buds upon their 
surface, and are incapable of developing them under any 
conditions. Other plants may produce them when cut off 
from the parent plant during the growing season. Such 
are the plum, apple, poplar, and hawthorn. The roots of 
the former perish if deprived of connection with the stem 
and leaves. The latter may strike out new stems and 
leaves for themselves. Plants like the plum are, therefore, 
capable of propagation by root-cuttings, i. e., by placing 
pieces of their roots in warm and moist earth. 

Tap-Roots* — All plants whose seeds readily divide into 
two parts, and whose stems increase externally by addi- 
tion of new rings of growth — the so-called dicotyledonous 
plants, or Exogens, have, at first, a single descending axis, 
the tap-root, which penetrates vertically into the ground. 
From this central tap-root, lateral roots branch out more 
or less regularly, and these lateral roots subdivide again 
and again. In many cases, especially at first, the lateral 
roots issue from the tap-root with great order and regu- 
larity, as much as is seen in tlie branches of the stem of a 
fir-tree or of a young grape vine. In older plants, this 
order is lost, because the soil opposes mechanical hindrances 
to regular development. In many cases the tap-root grows 
to a great length, and forms the most striking feature of 
the radication of the plant. In others it enters the ground 
but a little way, or is surpassed in extent by its side 
branches. The tap-root is conspicuous in the Canada 
thistle, dock, {Humex,) and in seedling fruit trees. The 



238 HOW CKOPS GROW. 

Tipper portion of the tap-root of the beet, turnip, carrot, 
and radish, expands tinder cultivation, and becomes a 
fleshy, nutritive mass, in which lies the value of these 
plants for agriculture. The lateral roots of other plants, 
as of the dahlia and sweet potato, swell out at their ex- 
tremities to tubers. 

Crown Roots. — MonocotyUdonous plants^ or Midogens, 
i. e., plants whose seeds do not split with ease into two 
nearly equal parts, and whose stems increase by inside 
growth, such as the cereals, grasses, lilies, palms, etc., 
have no single tap-root, but produce crown roots, i. e., 
a number of roots issue at once in quick succession from 
the base of the stem. This is strikingly seen in the onion 
and hyacinth, as well as in maize. 

Rootlets* — ^This term ^ve apply to the slender roots, 
usually not larger than a knitting needle, and but a few 
inches long, which are formed last in the order of growth, 
and correspond to the larger roots as twigs correspond to 
the branches of the stem. 

The Offices of the Root are threefold : 

1 . To fix the plant in the earth and maintain it, in most 
cases, in an upright position. 

2. To absorb nutriment from the soil for the growth of 
the entire plant, and, 

3* In case of many plants, especially of those whose 
terms of life extend through several or many years, to 
serve as a store-house for the future use of the plant. 

1. The Firmness with which a Plant is fixed in the 
Ground depends upon the nature of its roots. It is easy 
to lift an onion from the soil, a carrot requires much more 
force, while a dock may resist the full strength of a pow- 
erful man. A small beech or seedling apple tree, which 
has a tap-root, withstands the force of a wind that would 
prostrate a maize-plant or a poplar ,which has only side roots. 
In the nursery it is the custom to cut off the tap-root of 



THE VEGETATIVE ORGANS OF PLANTS, 239 

apple, peach, and other trees, when very young, in order 
that they may be readily and safely transplanted as occa- 
sion shall require. The depth and character of the soil, 
however, to a certain degree influence the extent of the 
roots and the tenacity of their hold. The roots of maize, 
which in a rich and tenacious earth extend but two or three 
feet, have been traceji to a length of ten or even fifteen 
feet in a light, sandy soil. The roots of clover, and espe- 
cially those of lucern, extend very deeply into the soil, 
and the latter acquire in some cases a length of 30 feet. 
The roots of the ash have been known as much as 95 feet 
long. {Jour. Boy, Ag. Soc, YI, p. 342.) 

2. Hoot'obeorption. — The Office of absorbing Plant 
Food from the Soil is one of the utmost importance, and 
one for which the root is most wisely adapted by the fol- 
lowing particulars, viz.: 

a. The Delicacy of its Structure, especially that of the 
newer portions, the cells of which are very soft and absor- 
bent, as may be readily shown by immersing a young 
seedling bean in solution of indigo, when the roots shortly 
acquire a blue color from imbibing the liquid, while the 
stem, a portion of Avhich in this plant extends below the 
seed, is for a considerable time unaltered. 

It is a common but erroneous idea that absorption from 
the soil can only take place through the ends of the roots 
— through the so-called spongioles. On the contrary, the 
extreme tips of the rootlets cannot take up liquids at all. 
(Ohlerts, loc. cit., see p. 249.) All other parts of the roots 
Avhich are still young and delicate in surface-texture, are 
constantly active in the work of imbibing nutriment from 
the soil. 

In most perennial plants, indeed, the larger branches of 
the roots become after a time coated with a corky or oth- 
erwise nearly impervious cuticle, and the function of ab- 
sorption is then transferred to the rootlets. This is demon- 



240 : HOW CROPS geow. 

strated by placing the old, brown-colored roots of a plant 
in water, bnt keeping tbe delicate and unindiirated ex- 
tremities above the liquid. Thus situated, the plant with- 
ers nearly as soon as if its root-surface were all exposed to 
the air. 

b. Its Rapid Extension in Length, and the yast Sur- 
face which it puts in contact with the soil, further adapts 
the root to the work of collecting food. The length of 
roots in a direct line from the point of their origin is not, in- 
deed, a criterion by which to judge of the efficiency where- 
with the plant to which they belong is nourished; for 
two plants may be equally flourishing — be equally fed by 
their roots — when these organs, in one case, reach but one 
foot, and in the other extend two feet from the stem to 
which they are attached. In one case, the roots would be 
fewer and longer ; in the other, shorter and more numer- 
ous. Their aggregate length, or, more correctly, the ag- 
gregate absorbing surface, would be nearly the same in 
both. 

The Medium in which Roots Grow has a great influence 
on their extension. When they are situated in concen- 
trated solutions, or in a very fertile soil, they are short, 
and numerously branched. Where their food is sparse, 
they are attenuated, and bear a comparatively small num- 
ber of rootlets. Illustrations of the former condition are 
often seen. Bones and masses of manure are not infre- 
quently found, completely covered and penetrated by a 
fleece of stout roots. On the other hand, the roots which 
grow in poor, sandy soils, are very long and slender. 

Nobbe has described some experiments which com- 
pletely establish the point under notice. ( Vs. jSL, IV, p. 
212.) He allowed maize to grow in a poor clay soil, con- 
tained in glass cylinders, each vessel having in it a quan- 
tity of a fertilizing mixture disposed in some peculiar man- 
ner for the purpose of observing its influence on the roots. 
When the plants had been nearly four months in growth. 



THE VEGETATIVE ORGANS OF PLANTS. 241 

the vessels were placed in water until the earth was soft- 
ened, so that by gentle agitation it could be completely- 
removed from the roots. The latter, on being suspended 
in a glass vessel of water, assumed nearly the position they 
had occupied in the soil, and it was observed that where 
the fertilizer had been thoroughly mixed with the soil, 
the roots uniformly occupied its entire mass. 

Where the fertihzer had been placed in a horizontal 
layer at the depth of about one inch, the roots at that 
depth formed a mat of the finest fibers. Where the fer- 
tilizer was situated in a horizontal layer at half the depth 
of the vessel, just there the root-system was spheroidally 
expanded. In the cylinders where the fertilizer formed a 
vertical layer on the interior walls, the external roots were 
developed in numberless ramifications, while the interior 
roots were comparatively unbranched. In pots, where 
the fertilizer was disposed as a central vertical core, the 
inner roots were far more greatly developed than the outer 
ones. Finally, in a vessel where the fertilizer was placed 
in a horizontal layer at the bottom, the roots extended 
through the soil, as attenuated and slightly branched 
fibers, until they came in contact with the lower stratum, 
where they greatly increased and ramified. In all cases, 
the principal development of the roots occurred in the 
immediate vicinity of the material which could furnish 
them with nutriment. 

It has often been observed that a plant whose aerial 
branches are symmetrically disposed about its stem, has 
the larger share of its roots on one side, and again we find 
roots which are thick with rootlets on one side, and nearly 
devoid of them on the other. 

Apparent Search for Food. — It would almost appear, 
on superficial consideration, that roots are endowed with a 
kind of intelligent instinct, for they seem to go in search 
of nutriment. 
11 



242 HOW CROPS GROW. 

The roots of a plant make their first issue independently 
of the nutritive matters that may exist in their neighbor- 
hood. They are organized and put forth from the plant 
itself, no matter how fertile or sterile the medium that 
surrounds them. When they attain a certain develop- 
ment, they are ready to exercise their office of collecting 
food. If food be at hand, they absorb it, and, together 
with the entire plant, are nourished by it — they grow in 
consequence. The more abundant the food, the better they 
are nourished, and the more they multiply. The plant 
sends out rootlets in all directions; those which come in 
contact w^ith food, live, enlarge, and ramify ; those which 
find no nourishment, remain undeveloped or perish. 

The Quantity of Roots actually attached to any plant 
is usually far greater than can be estimated by roughly 
lifting them from the soil. To extricate the roots of 
wheat or clover, for example, from the earth, completely, 
is a matter of no little difficulty. Schubart has made the 
most satisfactory observations we possess on the roots of 
several important crops, growing in the field. He sepa- 
rated them from the soil by the following expedient : An 
excavation was made in the field to the depth of 6 feet, and 
a stream of water was directed against the vertical wall 
of soil until it was washed away, so that the roots of the 
plants growing in it were laid bare. The roots thus ex- 
posed in a field of rye, in one of beans, and in a bed of gar- 
den peas, presented the appearance of a mat or felt of white 
fibers, to a depth of about 4 feet from the surface of the 
ground. The roots of winter wheat he observed as deep 
as 7 feet, in a light subsoil, forty-seven days after sowing. 
The depth of the roots of winter wheat, winter rye, and 
winter colza, as well as of clover, was 3-4 feet. The roots 
of clover, one year old, were 3|- feet long, those of two- 
year-old clover but 4 inches longer. The quantity of roots 
in per cent of the entire plant in the dry state was found 
to be as follows. ( Ghem. Ackersmann^ I, p. 193.) 



THE VEGETATIVE ORGANS OP PLANTS. 243 

Winter wheat — examined last of April 40o|o 

" " " " "May 23" 

" rye " " " April 34" 

Peas examined four weeks after sowing 44 " 

" " at the time of blossom 24" 

Hellriegel has likewise studied the radication of barley 
and oats, {Iloff^ Jahreshericht, 1864, p. 106.) He raised 
plants in large glass pots, and separated their roots from 
the soil by careful washing with water. He observed that 
directly from the base of the stem 20 to 30 roots branch 
off sideways and downward. These roots, at their point 
of issue, have a diameter of ^ l^^ of an inch, but a little 
lower the diameter diminishes to about ^|j^„ of an inch. 
Retaining this diameter, they pass downward, dividing 
and branching to a certain depth. From these main roots 
branch out innumerable side roots, which branch again, 
and so on, filling every crevice and pore of the soil. 

To ascertain the total length of root, Hellriegel weighed 
and ascertained the length of selected average portions. 
Weighing then the entire root-system, he calculated the 
entire length. He estimated the length of the roots of a 
vigorous barley plant at 128 feet, that of an oat plant at 
150 feet.* He found that a smaU bulk of good fine soil 
sufiiced for this development ; ^ \^^ cub. foot, (4 x 4 x 2^ |^ in.,) 
answered for a barley plant ; ^ \^^ cub. foot for an oat plant, 
in these experiments. 

Hellriegel observed also that the quality of the soil in- 
fluenced the development. In rich, porous, garden-soil, a 
barley plant produced 128 feet of roots, but in a coarse- 
grained, compactor soil, a similar plant had but 80 feet of 
roots. 

Root-Hairs. — ^The real absorbent surface of roots is, in 
most cases, not to be appreciated without microscopic aid. 
The roots of the onion and of many other bulbs, i. e., the 
fibers which issue from the base of the bulbs, are perfectly 

* Ehenish feet. 



244 



HOW CEOrS GROW. 



smooth and unbranched throughout their entire length. 
Other agricultural plants have roots 
which are not only visibly branched, 
but whose finest fibers are more or 
less thickly covered with minute 
hairs^ scarcely perceptible to the un- 
assisted eye. These root-hairs consist 
always of tubular elongations «of the 
external root-cells, and through them 
the actual root-surface exposed to the 
soil becomes something almost incal- 
culable. The accompanying figures 
illustrate the appearance of root-hairs. 
Fig. 38 represents a young, seed- 
ling, mustard-plant. A is the plant, 
as carefully lifted from the sand in 
which it grew, and JB the same plant, 
freed from adhering soil by agitating 
in water. The entire root, save the 
tip, is thickly beset with hairs. In 
fig. 39 a minute portion of a barley- 
root is shown highly magnified. The 
hairs are seen to be slender tubes that 
proceed from, and form part of, the 

outer cells of the root. 

The older roots lose their 

hairs, and sufier a thickening of 

the outermost layer of cells by 

the deposition of cork. These 

dense-walled and nearly imjDer- 

vious cells cohere together and 

constitute a rind, which is not 

found in the young and active 

roots. 

As to the development of 

the root-hairs, they are more 




Fig. Zi 




THE VEGETATIVE ORGANS OF PLANTS. 245 

abundant in poor than in good soils, and appear to be 
most numerously produced from roots which have other- 
wise a dense and unabsorbent surface. The roots of those 
plants which are destitute of hairs are commonly of con- 
siderable thickness and remain white and of delicate tex- 
ture, preserving tbeir absorbent power throughout the 
whole time that the plant feeds from the soil, as is the case 
with the onion. 

The Silver Fir, {Abies pectinafa,) has no root-hairs, but 
its rootlets are covered with a very delicate cuticle highly 
favorable to absorption. The want of root-hairs is further 
compensated by the great number of rootlets which are 
formed, and which, perishing mostly before they become 
superficially indurated, are continually replaced by new 
ones during the growing season. (Schacht, J)er Baum, 
p. 165.) 

Contact of Roots with the Soil.— The root-hairs, as 
they extend into the soil, are naturally brought into close 
contact with its particles. This contact is much more in- 
timate than has been usually supposed. If w^e carefully 
lift a young wheat-plant from dry earth, we notice that 
each rootlet is coated with an envelope of soil. This ad- 
heres with considerable tenacity, so that gentle shaking 
fails to displace it, and if it be mostly removed by vigor- 
ous agitation or washing, the root-hairs are either found 
to be broken, or in many places inseparably attached to 
the particles of earth. 

Fig. 40 exhibits the appearance of a young w^heat- 
plant as lifted from the soil and pretty strongly shaken. 
JS, the seed ; b, the blade ; e, roots covered with hairs and 
enveloped in soil. Only the growing tips of the roots, w, 
which have not put forth hairs, come out clean of soil. 
Fig. 41 represents the roots of a wheat-plant one month 
older than those of the previous figure. In this instance 
not only the root-tips are naked as before, but the older 



246 



HOW CKOPS GROW. 




Fig. 40. 



Fig. 41 



THE VEGETATIVE ORGANS OF PLANTS. 



247 



parts of the primary roots, 6, and of the secondary roots, 
n, no longer retain the particles of soil ; the hairs upon 
them being, in fact, dead and decomposed. The newer 
parts of the root alone are clothed with active hairs, and 
to these the soil is firmly attached as before. The next il- 




Fig. 42. 

lustration, fig. 42, exhibits the appearance of root-hairs 
with adhering particles of earth, when magnified 800 di- 
ameters — A, root-hairs of wheat-seedling like fig. 40; JB, 
of oat-plant, both from loamy soil. Here is plainly seen 
the intimate attachment of the soil and root-hairs. The 



2^8 



HOW CROPS GROW. 



latter, in forcing tlieir way against considerable pressure, 
often expand around, and partially envelope, the particles 
of earth. 

Imbibition of Water by the Root. — The degree of 
force with which active roots imbibe the water of the soil 
is very great, is, in fact, sufficient to foi'ce the liquid upward 
into the stem and to exert a con- 
tinual pressure on all parts of the 
plant. When the stem of a plant 
in vigorous growth is cut off near 
the root, and a pressure-gauge is 
attached to it as in fig. 43, we 
have the means of observing and 
measuring the force with which 
the roots absorb water. The pres- 
sure-gauge contains a quantity of 
mercury in the middle reservoir, 
^, and the tube, c. It is attached 
to the stem of the plant, p^ by a 
stout india-rubber pipe, §'.* For 
accurate measurements the space, 
a and 5, should be filled with wa- 
ter. Thus arranged, it is found 
that water will enter a through 
the stem, and the mercury will 
rise in the tube, e, until its pres- 
Fig. 43. sure becomes sufficient to balance 

the absorptive power of the roots. Hales, who first ex- 
perimented in this manner 140 years ago, found in one 
instance, that the pressure exerted on a gauge attached in 
spring-time to the stump of a grape vine, supported a 
column of mercury 32^ inches bigh, which is equal to a 
column of water of 36^ ft. Hofmeister obtained on other 
plants, rooted in pots, the following results : 




* For experimenting on small plants, a simple tube of glass may be adjusted 
to the stump vertically by belp of a rubber connector. 



THE VEGETATIVE OKGANS OF PLANTS. 249 

Bean {Phaseolus multiflorus) 6 inches of mercury. 
Nettle - - - - 14 « " 

Vine - - - - 29 '' " 

Seat of Absorptive Force.— Dutrochet demonstrated 
that this power resides in the surface of the young and 
active roots. At least, he found that absori^tion was ex- 
erted with as much force when the gauge was applied to 
near the lower extremity of a root, as when attached in 
the vicinity of the stem. In fact, when other conditions 
are alike, the column of liquid sustained by the roots of a 
plant is greater, the less the length of stem that remains 
attached to them. The stem thus resists the rise of liquid 
in the plant. 

While the seat of absorptive power in the root lies near 
the extremities, it appears from the experiments of Ohlerts 
that the extremities themselves are incapable of imbibing 
water. In trials with young pen, flax, lupine, and horse- 
radish plants with unbranched roots, he found that they 
withered speedily when the tips of the roots were immers- 
ed for about one-fourth of an inch in water, the remaining 
parts being in moist air. Ohlerts likewise proved that 
these plants flourish when only the middle part of their 
roots is immersed in Avater. Keeping the root-tips, the 
so-called spongioles, in the air, or cutting them away alto- 
gether, was without apparent eSect on the freshness and 
vigor of the plants. The absorbing surfxce would thus 
appear to be confined to those portions of the root upon 
which the development of root-hairs is noticed. 

The absorbent force is manifested by the active rootlets, 
and most vigorously when these are in the state of most 
rapid development. For this reason we find, in case of the 
vine, for example, that during the autumn, when the plant 
is entering upon a period of repose from growth, the ab- 
sorbent power is trifling. The efiect of this forcible en- 
trance of water into the plant is oftentimes to cause the 
11* 



250 HOW CEOPS GROW. 

exudation of it in drops upon the foliage. This may be 
noticed upon newly sprouted maize, or other cereal j)lants, 
where the water escapes from the leaves at their extreme 
tips, especially when the germination has i^roceeded under 
the most favorable conditions for rapid development. 

The bleeding of the vine, when severed in the spring- 
time, the abundant flow of sap from the sugar-maple, and 
the water-elm, are striking illustrations of this imbibition 
of water from the soil by the roots. These examples are, 
indeed, exceptional in degree, but not in kind. Hofmeister 
has shown that the bleeding of a severed stump is a gen- 
eral fact, and occurs with all plants when the roots are 
active, when the soil can supply them abundantly with 
water, and when the tissues above the absorbent parts are 
full of this liquid. When it is otherwise, water may be 
absorbed from the gauge into the stem and large roots, un- 
til the conditions of activity are renewed. 

Of the external circumstances that influence the absorp- 
tive power of the root, may be noticed that of tempera- 
ture. By observing a gauge attached to the stump of 
a plant during a clear summer day, it will be usually no- 
ticed that the mercury begins to rise in the morning as 
the sun warms the soil, and continues to ascend for a num- 
ber of hours, but falls again as the sun declines. Sachs 
found in some of his experiments that at a temperature of 
41° F., absorption, in case of tobacco and squash plants, 
was nearly or entirely supjiressecl, but was at once renewed 
by plunging the pot into warm water. 

The external supplies of watei-, — in case a plant is sta- 
tioned in the soil, the degree of moisture contained in this 
medium, — obviously must influence, not perhaps the im- 
bibing force, but its manifestation. 

The Rate of Absorption is subject to changes depend- 
ent on other causes not well understood. Sachs observed 
that the amount of liquid which issued from potato stalks 



THE VEGETATIVE OEGANS OF PLANTS. 251 

cut off just above the ground, underwent great and con- 
tinual variation from hour to hour (during rainy weather) 
when the soil was saturated with water and when the 
thermometer indicated a constant temperature. Hofmeister 
states that the formation of new roots and buds on the 
stump is accompanied by a sinking of the water in the 
pressure-gauge. 

Absorption of Nutriment from the Soil.— The food of 
the plant, so far as it is derived from the soil, enters it in 
a state of solution, and is absorbed with the water which is 
taken up by the force acting in the rootlets. The absorp- 
tion of the matters dissolved in water is in some degree 
independent of the absorption of the water itself, the plant 
having, to a certain extent, a selective power. 

3. The Root as a Magazine. — In fleshy roots, like 
those of the carrot, beet, and turnip, the absorption of 
nutriment from the soil takes place principally, if not en- 
tirely, by means of the slender rootlets which proceed 
abundantly from all parts of the main or tap-root, and es- 
pecially from its lower extremity ; while the fleshy portion 
serves as a magazine in which large quantities of pectose, 
sugar, etc., are stored up during the first year's growth 
of these, (in our latitude,) biennial plants, to supply the 
wants of the flowers and seed which are developed the 
second year. When one of these roots is put in the 
ground for a second year and produces seed, it is found to 
be quite exhausted of the nutritive matters which it pre- 
viously contained in so large quantity. 

In cultivation, the farmer not only greatly increases the 
size of these roots and the stores of organic nutritive ma- 
terials they contain, but by removing them from the 
ground in autumn, he employs to feed himself and his cat- 
tle the substances that nature primarily designed to nour- 
ish the growth of flowers and seeds during another sum- 
mer. 



252 HOW CROPS GEOW. 

Soil-Roots: Water-Roots: Air -Roots. — We may dis- 
tinguish, according to the medium in which they are fonned 
and grow, three kinds of roots, viz. : soil-roots^ water-roots^ 
and air-roots. 

Most agricultural plants, and indeed by far the greater 
number of all plants found in temperate climates, have 
roots adapted exclusively to the soil, and which perish by 
drying, if long exposed to air, or rot, if immersed for a 
time in water. 

Many aquatic plants, on the other hand, die if their 
roots be removed from water, or from earth saturated 
with water. 

Air-roots are not common except among tropical plants. 
Indian corn, however, often throws out roots from the 
lower joints of the stem, which extend through the air 
several inches before they reach the soil. The Banyan of 
India sends out roots from its branches, which penetrate 
the earth in like manner. Many tropical plants, especially 
of the tribe of Orchids, emit roots which hang free in the 
air, and never come in contact with water or soil. 

A plant, known to botanists as the Zamia spiralis, not 
only throws out air-roots, c c, Fig. 44, from the crown of 
the main soil-root, but the side rootlets, J, after extending 
some distance horizontally in the soil, send from the same 
point, roots downward and upward, the latter of which, 
d, pass into and remain permanently in the air. A is the 
stem of the plant. (Schacht, Anatomie der Gewiichse, Bd. 
II, p. 151.) 

Some plants have roots which are equally able to exist 
and perform their functions, whether in the soil or sub- 
merged in water. Many forms of vegetation found in 
our swamps and marshes are of this kind. Of agricul- 
tural x^lants, rice is an example in point. Rice will grow 
in a soil of ordinary character, in respect of moisture, as 
the upland cotton-soils, or even the pine-barrens of the 
Carolinas. It flourishes admirably in the tide swamps of 



THE VEGETATIVE OEGANS OP PLANTS. 253 

the coast, where the land is laid under water for weeks at 
a time during its growth, and it succeeds equally well in 
fields which are flowed from the time of planting to that 
of harvesting. (Russell. JSTorth America, its Agriculture 
and Climate, p. 176.) The willow and alder, trees which 
grow on the margins of streams, send a part of their roots 
into soil that is constantly saturated with water, or into 




Fig. 44. 

the water itself; while others occupy the merely moist or 
even dry earth. 

Plants that customarily confine their growth to the soil, 
occasionally throw out roots as if in search of water, and 
sometimes choke up drain-pipes or even wells, by the pro- 
fusion of water-roots which they emit. 

At Welbeck, England, a drain was completely stopped 
by roots of horseradish plants at a depth of 7 feet. At 
Thomsby Park, a draui 16 feet deep was stopped en- 



254 now CROPS grow. 

tirely by the roots of gorse, growing at a distance of 6 
feet from the drain. {Jour. JRoy. Ag. /Soe., 1, 364.) 

In New Haven, Conn., certain wells are so obstructed by 
the aquatic roots of the elm trees, as to require cleaning 
out every two or three years. 

This aquatic tendency has been repeatedly observed in 
the poplar, cypress, laurel, turnip, mangel-wurzel, and 
grasses. 

Henrici surmised that the roots which most cultivated 
plants send down deep into the soil, even when the latter 
is by no means porous or inviting, are designed especially 
to bring up water from the subsoil for the use of the plant. 
The following experiment was devised for the purpose of 
testing the truth of this view. On the 13th of May, 
1862, a young raspberry plant, having but two leaves, 
w^as transplanted into a large glass funnel filled with gar- 
den soil, the throat of the funnel being closed with a paper 
filter. The funnel was supported in the mouth of a large 
glass jar, and its neck reached nearly to the bottom of the 
latter, where it just dipped into a quantity of water. The 
soil in the funnel was at first kept moderately moist by 
occasional waterings. The plant remained fresh and 
slowly grew, putting forth new leaves. After the lapse 
of several weeks, four strong roots penetrated the filter 
and extended down the empty funnel-neck, through which 
they emerged, on the 21st of June, and thenceforward 
spread rapidly in the water of the jar. From this time 
on, the soil was not watered any more, but care was taken 
to maintain the supj^ly in the jar. The plant continued to 
develope slowly ; its leaves, however, did not acquire a 
vivid green color, but remained pale and yellowish ; they 
did not wither until the usual time late in autumn. The 
roots continued to grow, and filled the water more and 
more. Near the end of December the plant had 7-8 
leaves, and a height of 8 inches. The water-roots were 
vigorous,. very long, and beset with numerous fibrils and 



THE VEGETATIVE ORGANS OF PLANTS. 255 

buds. In the funnel tube the roots made a perfect tissue 
of fibers. In the dry earth of the funnel they were 
less extensively developed, yet exhibited some juicy buds. 
The stem and the young axillary leaf-buds were also full 
of sap. The water-roots being cut away, the plant was 
put into garden soil and placed in a conservatory, where 
it grew vigorously, and in May bore two offshoots. 

The experiment would indicate that plants may extend 
a portion of their roots into the subsoil chiefly for the pur- 
pose of gathering supplies of water. {Henneberg^s Jour, 
far Zandwirthschaft^ 1863, p. 280.) This growth towards 
water must be accounted for on the principles asserted in 
the paragraph — Apparent Search for Food, (p. 241). 

The seeds of many ordinary land plants — of plants, in- 
deed, that customarily grow in a dry soil, such as the bean, 
squash, maize, etc., — will readily germinate in moist cot- 
ton or saw-dust, and if, when fairly sprouted, the young 
plants have their roots suspended in water, taking care 
that the seed and stem are kept above the liquid, they will 
continue to grow, and if duly supplied with nutriment 
will run through all the customary stages of development, 
producing abundant foliage, flowering, and jDerfecting seeds, 
without a moment's contact of their roots with any soil. 
(See Water- Culture, p. 167.) 

If plants thus growing with their roots in a liquid me- 
dium, after they have formed several large leaves, be care- 
fully transplanted to the soil, they wilt and perish, unless 
frequently watered ; whereas similar plants started in the 
soil, may be transplanted without suffering in the slight- 
est degree, though the soil be of the usual dryness, and 
receive no water. 

The water-bred seedlings, if abundantly watered as 
often as the foliage Avilts, recover themselves after a time, 
and thenceforward continue to grow without the need of 
watering. 

It might appear that the first-formed water-roots are in- 



256 HOW CROPS GROW. 

capable of feeding the plant from a dry soil, and hence 
the soil mnst be at first j)rofusely watered ; after a time, 
however, new roots are thrown out, which are adapted to 
the altered situation of the plant, and then the gro^yth 
proceeds in the usual manner. 

The reverse experiment would seem to confirm this 
view. If a seedling that has grown for a short time only 
in the soil, so that its roots are but twice or thrice branch- 
ed, have these immersed in water, the roots already form- 
ed mostly or entirely perish in a short time. They indeed 
absorb water, and the plant is sustained by them, but im- 
mediately new roots grow from the crown with great ra- 
pidity, and take the j^lace of the original roots, which 
become disorganized and useless. It is, however, only the 
young and active rootlets, and those covered with hairs, 
which thus refuse to live in water. The older parts of the 
roots, which are destitute of fibrils and which have nearly 
ceased to be active in the work of absorption, are not af- 
fected by the change of circumstance. These facts, which 
are due to the researches of Dr. Sachs, ( Vs. St., 2, p. 13,) 
would naturally lead to the conclusion that the absorbent 
surface of the root undergoes some structural change, or 
produces new roots* with modified characters, in order to 
adapt itself to the medium in which it is placed. It 
would appear that when this adaptation proceeds raj^idly, 
the plant is not permanently retarded in its growth by a 
gradual change in the character of the medium which 
surrounds its roots, as may happen in case of rice and 
marsh-plants, when the saturated soil in which they may 
be situated at one time, is slowly dried. Sudden changes 
of medium about the roots of plants slow to adapt them- 
selves, would be fatal to their existence. 

ISTobbe has, however, carefully compared the roots of 
buckwheat, as developed in the soil, with those emitted in 
water, without being able to observe any structural differ- 
ences. The facts detailed above admit of partial, if not 



THE VEGETATIVE ORGANS OF PLANTS. 257 

complete explanation, without recourse to the supposition 
that soil and water-roots are essentially diverse in nature. 
When a plant which is rooted in the soil is taken up so 
that the fibrils are not broken or inj ured, and set into wa- 
ter, it does not suffer any hindrance in growth, as Sachs 
has found by late experiments. (Experimental JPhysi- 
ologie^ p. 177.) Ordinaiily, the suspension of growth and 
decay of fibrils and rootlets is due, doubtless, to the 
mechanical injury they suffer in removing from the soil. 
Again, when a plant that has been reared in water is 
planted in earth, similar injury occurs in packing the soil 
about the roots, and moreover the fibrils cannot be brought 
into that close contact with the soil which is necessary for 
them to supply the foliage with water ; hence the plant 
wilts, and may easily perish unless profusely watered or 
shielded from evaporation. 

The issue of water or soil-roots, either or both, from 
the same plant, according to the circumstances in which it 
is placed, finds something analogous in reference to air- 
roots. As before stated, these chiefly occur on tropical 
plants, or in shaded, warm, and very moist situations. 
Schacht informs us that in the dark and humid forest ra- 
vines of Madeira and Teneriffe, the Laurus Canariensis^ a 
large tree, sends out from its stem during the autumn rains, 
a profusion of fleshy air-roots, which cover the trunk with 
their interlacing branches and grow to an inch in thick- 
ness. The following summer, they dry away and fall to 
the ground, to be replaced by new ones in the ensuing au- 
tumn. {Der £aum, p. 172.) 

The formation of air-roots may be very easily observed by filling a tall 
vial with water to the depth of half an inch, inserting therein a branch of 
a common house-plant, the Tradescantia zebrina, s,o that the cut end of 
the stem shall stand in the water, and finally corking the vial air-tight. 
The plant, which is very tenacious of life, and usually grows well in 
spite of all neglect, is not cheeked in its vegetative development by the 
treatment just described, but immediately begins to adapt itself to its 
new circumstances. In a few days, if the temperature be 70° or there- 
about, air-roots will be seen to issue from the joints of the stem. These 



258 HOW CKOPS GROW. 

are fringed with a profusion of delicate hairs, and rapidly extend to a 
length of from one to two inches. The lower ones, if they cliancc to 
penetrate the water, become discolored and decay; the others, however, 
remain for a long time fresh, and of a white color. 

As already mentioned, Indian corn frequently produces 
air-roots. The same is true of the oat, of buckwheat, of 
the grape-vine, and of other plants of temperate re- 
gions when they are placed for some time in tropical con- 
ditions, i. e., when they grow in a rich soil and their over- 
ground organs are surrounded by a very warm and very 
moist atmosphere. 

It has been conjectured tbat these air-roots serve to ab- 
sorb moisture from the air and thus aid to maintain the 
growth of the plant. This subject has been studied by 
linger, Chatin, and Duchartre. The observers first named 
were led to conclude that these organs do absorb water 
from the air. Duchartre, however, denies their absorptive 
power. It is probably true that they can and do absorb 
to some extent the water that exists as vapor in the at- 
mosphere. At the same time they may not usually con- 
dense enough to make good the loss that takes place in 
other parts of the plant by evaporation. Hence the re- 
sults of Duchartre, which were obtained on the entire 
plant and not on the air-roots alone. {Elements de 
Botanique^ p. 216.) It certainly appears improbable that 
organs which only develope themselves in a humid atmos- 
phere, where the plant can have no lack of water, should 
be specially charged with the office of collecting moisture 
from the air. 

Root-Excretions. — ^It has been supposed that the roots 
of plants perform a function of excretion, the reverse of 
absorption — that plants, like animals, reject matters which 
are no longer of use in their organism, and that the re- 
jected matters are poisonous to the kind of vegetation 
from which they originated. De Candolle, an eminent 
French botanist, who first advanced this doctrine, founded 



I 



THE VEGETATIVE ORGANS OP PLANTS. 259 

it upon the observation that certain plants exude drops 
of liquid from their roots when these are placed in dry- 
sand, and that odors exhale from the roots of other plants. 
Numerous experiments have been instituted at various 
times for the purpose of testing this question. The most 
extensive inquiries we are aw'are of, are those of Dr. Al- 
fred Gyde, {Trans. Highland and Agr. jSoc, 1845-7, p. 
273-92). This experimenter planted a variety of agricul- 
tural plants, viz., wheat, barley, oats, rye, beans, peas, 
vetches, cabbage, mustard, and turnips, in pots filled either 
with garden soil, sand, moss, or charcoal, and after they had 
attained considerable growth, removed the earth, etc., from 
their roots by washing with water, using care not to in- 
jure or wound them, and then immersed the roots in ves- 
sels of pure water. The plants were allowed to remain 
in these circumstances, their roots being kept in darkness, 
but their foliage exposed to light, from three to seventeen 
days. In most cases they continued apparently in a good 
state of health. At the expiration of the time of experi- 
ment, the water which had been in contact with the roots 
was evaporated, and was found to leave a very minute 
amount of yellowish or brown matter, a portion of which 
was of organic and the remainder of mineral origin. Dr. 
Gyde concluded from his numerous trials, that plants do 
throw off organic and inorganic excretions similar in com- 
position to their sap ; but that the quantity is exceedingly 
small, and is not injurious to the plants which furnish 
them. 

In the hght of newer investigations touching the struc- 
ture of roots and their adaptation to the medium which 
happens to invest them, we may well doubt whether agri- 
cultural plants in the healthy state excrete any solid or 
liquid matters whatever from their roots. The familiar 
excretion of gum, resin, and sugar,* from the stems of 



* From the wounded bark of the Sugar Pine, (Finus Lanibertiana,) of Cali- 
fornia. 



260 HOW CROPS GEOW. 

trees appears to result from wounds or disease, and the 
matters whicli in the experiments of Gyde and others 
were observed to be communicated by the roots of plants 
to pure water, probably came either from the continual 
pushing off of the tips of the rootlets by the interior 
growing point — a process always naturally accompanying 
the growth of roots — or from the disorganization of the 
absorbent root-hairs. 

Under certain circumstances, small quantities of mineral 
salts may indeed diffuse out of the root-cells into the water 
of the soil. This is, however, no physiological action, 
but a purely physical process. 

Vitality of RootSi — It appears that in case of most 
plants the roots cannot long continue their vitality if their 
connection with the leaves be interrupted, unless, indeed, 
they be kept at a winter temperature. Hence weeds may 
be effectually destroyed by cutting down their tops ; al- 
though, in many cases, the process must be several times 
repeated before the result is attained. 

The roots of our root-crops, properly so-called, viz., 
beets, turnips, carrots, and parsnips, when harvested in au- 
tumn, contain the elements of a second year's growth of 
stem, etc., in the form of a bud at the crown of the root. 
If the crown be cut away from the root, the latter cannot 
vegetate, while the growth of the crown itself is not 
thereby prevented. 

As regards internal structure, the root closely resembles 
the stem, and what is stated of the latter on subsequent 
pages, applies in all essential points to the former. 

§2. 
THE STEM. 

Shortly after the protrusion of the rootlet from a ger- 
minating seed, the Stem makes its appearance. It has, in 
general, an upward direction, which in many plants is per- 



THE VEGETATIVE ORGANS OP PLANTS. 



261 



manent, while in others it shortly foils to the ground and 
grows thereafter horizontally. 

All plants of the higher orders have stems, though in 
many instances they do not appear above ground, but ex- 
tend beneath the surface of the soil, and are usually con- 
sidered to be roots. 

While the root, save in exceptional cases, does not de- 
velop other organs, it is the special function of the stem 
to bear the leaves, flowers, and seed, of the plant, and even 
in certain tribes of vegetation, like the cacti, which have 
no leaves, it performs the offices of these organs. In gen- 
eral, the functions of the stem are subordinate to those 
of the organs which it bears — ^the leaves and flowers. It 
is the support of these organs, and only extends in length 
or thickness with the apparent purpose of sustaining them 
either mechanically or nutritively. 

BudSo — In the seed the stem exists in a rudimentary 
state, associated with undeveloped leaves, forming a hud. 
The stem always proceeds at first from a bud, during all 
its growth is terminated by a bud at every growing point, 
and only ceases to be thus tipped when it fully accom- 
plishes its growth by the production of seed, or dies from 
injury or disease. iV > «»^ y/fj 

In the leaf-hud 
we find a number 11^^ Jllfmim ^-^^ 

of embryo leaves 
and leaf-like scales, 
in close contact and 
within each other, 
but all attached at 
the base, to a cen- 
tral conical axis, 
fig. 45. The open- 
ing of the bud con- 
sists in the lengthening of this axis, which is the stem, 
and the consequent separation of the leaves from each 





Fig. 45. 



262 HOW CEOPS GROW. 

other. If the rudimentary leaves of a bud be represented 
by a nest of flower-pots, the smaller placed within the 
larger, the stem may be signified by a rope of India- 
rubber passed through the holes in the bottom of the 
pots. The growth of the stem may now be shown by stretch- 
ing the rope,whereby the pots are brought away from each 
other, and the whole combination is made to assume the char- 
acter of a fully developed stem, bearing its leaves at regular 
intervals ; with these important differences, that the por- 
tions of stem nearest the root extend more rapidly than 
those above them, and the stem has within it the material 
and the mechanism for the continual formation of new 
buds, which unfold in successive order. 

In fig. 45, which represents the two terminal buds of a 
lilac twig, is shown not only the external appearance of 
the buds, which are covered with leaf-like scales, imbricated 
like shingles on a roof; but, in the section, are seen the 
edges of the undeveloped leaves attached to the conical 
axis. All the leaves and the whole stem of a twig of one 
summer's growth thus exist in the bud, in plan and in 
miniature. Subsequent growth is but the development 
of the plan. 

In the flower-hud the same structure is manifest, save 
that the rudimentary flowers and fruit are enclosed within 
the leaves, and may often be seen plainly on cutting the 
bud open. 

Culms ; K"odes ; Internodes. — The grasses and the com- 
mon cereal grains have single, unbranched stems, termed 
culms in botanical language. The leaves of these plants 
clasp the stem entirely at their base, and at this point is 
formed a well-defined, thickened knot or node in the stem. 
The portions of the stem between these nodes are termed 
internodes. 

Branching Stems. — Other agricultural plants besides 
those just mentioned, and all the trees of temperate cli- 



THE VEGETATIVE OKGANS OP PLAISTS. 263 

mates, have branching sterns^ originating in the following 
manner : As the principal or main stem elongates, so that 
the leaves arranged upon it separate from each other, 
we may find one or more side or axillary buds at the point 
where the base of the leaf or of the leaf-stalk unites with 
the stem. From these buds, in case their growth is not 
checked, side-stems or branches issue, which again sub- 
divide in the same manner into branchlets. 

In perennial plants, Avhen young, or in their young 
shoots, it is easy to trace the nodes and internodes, or the 
points where the leaves are attached and the intervening 
spaces, even for some time after the leaves, which only 
endure for one year, are fallen away. The nodes are mani- 
fest by the enlargement of the stem, or by the scar covered 
with corky matter, which marks the spot where the leaf- 
stalk was attached. As the stem grows older these indi- 
cations of its early development are gradually obliterated. 

In a forest where the trees are thickly crowded, the 
lower branches die away from want of light; the scars 
resulting from their removal are covered with a new 
growth of wood, so that the trunk finally appears as if it 
had always been destitute of branches, to a great height. 

When all the buds develop normally and in due propor- 
tion, the plant, thus regularly built up, has a symmetrical 
appearance, as frequently happens with many herbs, and 
also with some of the cone-bearing trees, especially the 
balsam-fir. 

Latent Buds. — Often, however, many of the buds re- 
main undeveloped either permanently or for a time. 
Many of the side-buds of most of our forest and fruit trees 
fail entirely to grow, while others make no progress until 
the summer succeeding their first appearance. When the 
active buds are destroyed, either by frosts or by pinching 
off, other buds that would else remain latent, are pushed 
into growth. In this way, trees whose young leaves are de- 
stroyed by spring frosts, cover themselves again after a 



264 HOW CEOPS GROW. 

time with foliage. In this way, too, the gardener molds a 
straggling, ill-shaped shrub or plant into almost any form 
he chooses ; for by removing branches and buds where 
they have grown in undue proportion, he not only checks 
excess, but also calls forth development in the parts before 
suppressed. 

Adventitious or irregular Buds are produced from the 
stems as well as older roots of many plants, when they are 
mechanically injured during the growing season. The 
soft or red maple and the chestnut, when cut down, habitu- 
ally throw out buds and new stems from the stump, and 
the basket- willow is annually polled, ov 2^ollarded^ to induce 
the growth of slender shoots from an old trunk. 

Elongation of Stems. — ^While roots extend chiefly at 
their extremities, we find the stem elongates equally, or 
nearly so, in all its contiguous parts, as is manifest from 
what has already been stated in illustration of its devel- 
opment from the bud. 

Besides the upx-ight stem, there are a variety of prostrate 
and in part subterranean stems, which may be briefly no- 
ticed. 

Runners and Layers are stems that are sent out hori- 
zontally just above the soil, and coming in contact with the 
earth, take root, forming new plants, which may thence- 
forward grow independently. The gardener takes advan- 
tage of these vSteras to propagate certain plants. The 
strawberry furnishes the most familiar example of runners, 
while many of the young shoots of the currant fall to the 
ground and become layers. The runner is a somewhat 
peculiar stem. It issues horizontally, and usually bears 
but few or no leaver. The layer does not differ from an 
ordinary stem, except by the circumstance, often accident- 
al, of becoming prostrate. Many plants which usually 
send out no layers, are nevertheless artificially layered by 
bending their stems or branches to the ground, or by at- 



THE VEGETATIVE OEGANS OF PLANTS. 265 

taching to them a ball or pot of earth. The striking out 
of roots from the layer is in many cases facilitated by cut- 
ting half off, twisting, or otherwise wounding the stem at 
the point where it is buried in the soil. 

The tillering of wheat and other cereals, and of many 
grasses, is the spreading of the plant by layers. The first 
stems that appear from these plants ascend vertically, but, 
subsequently, other stems issue, whose growth is, for a 
time, nearly horizontal. They thus come in contact with 
the soil, and emit roots from their lower joints. From 
these again grow new stems and new roots in rapid suc- 
cession, so that a stool produced from a single kernel of 
winter wheat, having perfect freedom of growth, has been 
known to carry 50 or 60 grain-bearing culms. (Hallet, 
Jour. Hoy. Soc. of Eng., 22, p. 372.) 

SuMcrranean Stems. — Of these there are three forms 
agriculturally interesting. They are usually thought to be 
roots, from the fact of existing below the surface of the 
soil. This circumstance is, however, quite accidental. 
The pods of the pea-nut ripen beneath the ground — the 
flower-stems lengthening and penetrating the earth as 
soon as the blossom falls ; but pea-nuts are not by any 
means to be confounded with roots. 

Root-stocks* — As before remarked, true roots are desti- 
tute of buds, and, we may add, of leaves. This fact dis- 
tinguishes them from the so-called creeping-root^ which is 
a stem that extends just below the surface of the soil, 
emitting roots throughout its entire length. At intervals 
along these root-stocJcs^ as they are appropriately named, 
scales are formed, which represent rudimentary leaves. 
In the axils of the scales may be traced the buds from 
which aerial stems proceed. Examples of the root-stock 
are very common. Among them we may mention the 
blood-root and pepper-root as abundant in the woods of 
the IlsTorthern and Middle States, and the quack-grass, 
12 



266 



HOW CBOPS GEOW. 



represented in fig. 46, which infests so many farms. Each 
node of the root-stock, being usually supplied with roots, 
and having latent buds, is ready to become an independ- 
ent growth the moment it is detached from its parent 
plant. In this way quack-grass becomes especially troub- 




rig. 46. 

lesome to the farmer, for, within certain limits, the more 
he harrows the fields where it has obtained a footing, the 
more does it spread and multiply. 

Suckers. — The rose, raspberry, and cherry, are examples 
of plants which send out subterranean branches, analogous 
to the root-stock. These coming to the surface, become 
aerial stems, and are then termed suckers. 

The Tuliers of most agricultural j)lants are fleshy en- 
largements of the extremities of subterranean stems. 
Their eyes are the points where the buds exist, usually 
three together, and where minute scales — rudimentary 
leaves — may be observed. The common potato and arti- 
choke are instances of tubers. Tubers serve excellently 
for propagation. Each eye, or bud, may become a new 
plant. From the quantity of starch, etc., accumulated in 
them, they are of great importance as food. The number 
of tubers produced by a potato-plant appears to be in- 
creased by planting origipally at a considerable depth, or 
by " hillmg up " earth around the base of the aerial stems 
during the early stages of its growth. 



THE VEGETATIVE OEGANS OF PLANTS. 267 

Bulbs are the lower parts of stems, greatly thickened, 
the internodes being undeveloped, while the leaves — usu- 
ally scales or concentric coats — are in close contact with 
each other. The bulb is, in fact, a fleshy, permanent bud, 
usually in part or entirely subterranean. From its apex, 
the proper stem, the foliage, etc., proceed; while from 
its base, roots are sent out. The structural identity 
of the bulb with a bud is shown by the fact that the onion, 
which furnishes the commonest example of the bulb, often 
bears bulblets at the top of its stem, in place of flowers. 
In like manner, the axillary buds of the tiger-lily are 
thickened and fleshy, and fall off as bulblets to the ground, 
where they produce new plants. 

Steuctuee op THE Stem. — The stem is so complicated 
in its structural composition that to discuss it fully w^ould 
occupy a volume. For our immediate purposes it is, 
however, only necessary to notice it very concisely. 

The rudimentary stem, as found in the seed, or the new- 
formed part of the maturer stem at the growing points 
just below the terminal buds, consists of cellular tissue, 
i. e., of an aggregate of rounded and cohering cells, which 
rapidly multiply during the vigorous growth of the plant. 

In some of the lower orders of vegetation, as in mush- 
rooms and lichens, the stem, if any exist, always preserves 
a purely cellular character ; but in all flowering plants the 
original cellular tissue of the stem, as well as of the root, 
is shortly penetrated by vascular tissue, consisting of ducts 
or tubes, which result from the obliteration of the hori- 
zontal partitions of cell-tissue, and by wood-cells, which are 
many times longer than wide, and the walls of which are 
much thickened by internal deposition. 

These ducts and wood-cells, together with some other 
forms of cells, are usually found in close connection, and 
are arranged in bundles, which constitute the fibers of the 
stem. They are always disposed lengthwise in the stem 
and branches. They are found to some extent in the soft- 



268 HOW CEOPS GROW. 

est herbaceous stems, while they constitute a large share 
of the trunks of most shrubs and trees. From the tough- 
ness which they possess, and the manner in which they 
are woven through the original cellular tissue, they give 
to the stem its solidity and strength. 

The flowering plants of temperate climates may be di- 
vided into two great classes, in c6nsequence of important 
and obvious differences in the structure of their stems and 
seeds. These are, 1, Endogenous or Monocotyledonous * 
and, 2, Exogenous or Dicotyledonous plants. As regards 
their stems, these two classes of plants differ in the ar- 
rangement of the vascular or woody tissue. 

Endogenous Plants are those whose stems enlarge by 
the formation of new wood in the interior, and not by the 
external growth of concentric layers. The seeds of endog- 
enous plants consist of a single piece — do not readily 
sjDlit into halves, — or, in botanical language, have but one 
cotyledon ; hence are called monocotyledonous. Indian 
corn, sugar cane, sorghum, wheat, oats, rye, barley, the 
onion, asparagus, and all the grasses, belong to this tribe 
of plants. 

If a stalk of maize, asparagus, or bamboo, be cut across, 
the bundles of ducts are seen disposed somewhat uni- 




formly throughout the section, though less abundantly to- 
wards the center. On splitting the fresh stalk lengthwise, 
the vascular bundles may be torn out like strings. At 
the nodes, where the stem branches, or where leaf-stalks 
are attached, the vascular bundles likewise divide and 
form a net-work, or plexus. In a ripe maize-stalk which is 
exposed to circumstances favoring decay, the soft cell-tis- 
sue first suffers change and often quite disappears, leaving 



THE VEGETATIVE ORGANS OF PLANTS. 269 

tlie firmer vascular bundles unaltered in form. A portion 
of the base of such a stalk, cut lengthwise, is represented 
in figure 47, where are seen the duct-fibers arranged par- 
allel to each other in the internodes, and curiously inter- 
woven and branched at the nodes, either those, a and ^, 
from which roots issue, or that, c, which was clasped by 
the base of a leaf. 

The endogenous stem, as represented in the maize-stalk, 
has no well-defined larh that admits of being stripped off 
externally, and no separate central pith of soft cell-tissue 
free from vascular bundles. It, like the aerial portions of 
all flowering plants, is covered with a skin, or epidermis^ 
•composed usually of one or several layers of flattened 
cells, whose walls are thick, and far less penetrable to 
fluid than the delicate texture of the interior cell-tissue. 
The stem is denser and harder at the circumference than 
towards the center. This is due to the fact that the fibers 
are more numerous and older towards the outside of the 
stem. The newer fibers, as they continually form, grow 
in the inside of the stem, and hence the designation endog- 
enous, which in plain English means inside-grower. 

In consequence of this inner growth, the stems .of most 
woody endogens, as the palms, after a time become so in- 
durated externally, that all lateral expansion ceases, and 
the stem increases only in height. It grows, nevertheless, 
internally, new fibers developing in the softer portions, 
until, in some cases, the tree dies because its interior is so 
closely packed with fibers that the formation of new ones, 
and the accompanying vital processes, become impossible. 

In herbaceous endogens the soft stem admits the indefi- 
nite growth of new vascular tissue. 

The stems of the grasses are hollow, except at the 
nodes. Those of the rushes have a central pith free from 
vascular tissue. 

The Minute Structure of the Endogenous Stem is ex- 
hibited in the accompanying cuts, which represent highly 



270 



HOW CEOPS GEOW. 



magnified sections of a Vascular bundle or fiber from the 
maize-stalk. As before remarked, the stem is composed 
of a ground- work of delicate cell-tissue, in which bundles 
of vascular tissue are distributed. Fig. 48 represents a 
cross section of one of these bundles, c, </, A, as well as 




of a portion of the surrounding cell-tissue, a, a. The 
latter consists of quite large cells, which, being but loosely 
packed together, have between them considerable inter- 
cellular spaces, ^. The vascular bundle itself is composed 
externally of narrow, thick-walled cells, of which those 
nearest the exterior of the stem, A, are termed bast-cells^ 
as they correspond in character and position to the cells 



THE VEGETATIVE ORGANS OF PLANTS. 



271 



of the bast or inner bark of our common trees ; those 
nearest the centre of the stem, c, are vjood-cells. In the 
maize stem, bast and wood-cells are quite alike, and 
are distinguished only hj their position. In other plants, 
they are often unlike as regards length, thickness, and pli- 
ability, though still, for the most part, similar in form. 
Among the wood-cells we observe a number of ducts, d, 
^,y, and between these and the bast-cells is a delicate and 
transparent tissue, g, which is the camMiim — in which all 
the groicth of the bundle goes on until it is complete. On 





Fig. 49. 

either hand is seen a remarkably large duct, 5, J, while the 
residue of the bundle is composed of long and rather 
thick-walled wood-cells. 

Our understanding of these parts will be greatly aided 
by a study of fig. 49, Avhich represents a section made 
vertically through the bundle from c to A, cutting the va- 
rious tissues and reveahng more of their structure. In this 
th6 letters refer to the same parts as in the former cut : 
«, «, is the cell-tissue, enveloping the vascular bundle ; 
the cells are observed to be much longer than wide, but 
are separated from each other at the ends as well as sides 



272 HOW CEOPS GEOW. 

by an imperforate membrane. The wood and bast-cells, c, 
A, are seen to be long, narrow, thick-walled cells running 
obliquely to a point at either end. The wood-cells of oak, 
hickory, and the toughest woods, as well as the bast-cells 
of flax and hemp, are quite similar in form and appearance. 
The proper ducts of the stem are next in the order of our 
section. Of these there are several varieties, as ring-ducts, 
d ; spiral ducts, e ; dotted ducts, f. These are continuous 
tubes produced by the resorption of the transverse mem- 
branes that once divided them into such cells as a, a, and 
they are thickened internally by ring-like, spiral, or punc- 
tate depositions of cellulose, (see fig. 32, p. 227.) Wood- 
cells that consist exclusively of cellulose are pliant and 
elastic. It is the deposition of lignin in their walls which 
renders them stiff and brittle. 

At g, the cambium tissue is observed to consist of deli- 
cate cylindrical cells. Among these, partial resorption of 
the separating membrane often occurs, so that they com- 
municate directly with each other through sieve-like parti- 
tions, and become continuous channels or ducts, (sieve-cells, 
p. 280.) 

The cambium is the seat of growth by cell-formation. 
Accordingly, when a vascular bundle has attained maturi- 
ty, it no longer possesses a cambium ; the latter has grown 
away from it, has reproduced itself in originating a new 
vascular bundle, which, in case of the endogens, branches 
off from the present bundle, and with exogens, runs paral- 
lel with, and exterior to the latter. 

To complete our view of the vascular bundle, fig. 50 
represents a vertical section made at right angles to the 
last, cutting two large ducts, b, b ; a, a, is cell-tissue ; c, 
c, are bast or wood-cells less thickened by interior deposi- 
tion than those of fig. 49 ; d, is n ring and spiral duct ; b, 
b, are large dotted ducts, which exhibit at (/, g, the places 
Avhere they were once crossed by the double membrane 
composing the ends of two adhering cells, by whose ab- 



1 



THE VEGETATIVE OKGAXS OF PLANTS. 



273 



sorption and removal an uninterrupted tube has been 
formed. In these large dotted ducts there appears to be 
no direct communication with the surrounding cells 
through their sides. The dots or pits are simply very thin 
points in the cell-wall, through which sap may soak or 
diffuse laterally, but not flow. When the cells become 
mature and cease growth, the pits often become pores by 




Fig. 50. 



absorption of the membrane, so that the ducts thus enter 
into direct communication with each other. 

Exogenous plants are those whose stems continually 
enlarge in diameter by the formation of new tissue near 
the outside of the stem. They are outside-growers. Their 
seeds are usually made up of two loosely united parts, or 
cotyledons, wherefore they are designated dicotyledonous. 
All the forest trees of temperate climates, and, among 
agricultural plants, the bean, pea, clover, potato, beet, tur- 
nip, flax, etc., are exogens. 

In the exogenous stem the bundles of ducts and fibers 
that appear in the ccll-tissjue are always formed just within 
12* 



274 HOW CEOPS GT.OW. 

the epidermis. They occur at first separately, as in the 
endogens, but instead of being scattered throughout the 
cell-tissue, are disposed in a circle. As they grow, they 
usually close up to a ring or zone of wood, which, within, 
incloses unaltered cell-tissue — the pith — and without, in 
shrubs and trees, is covered by rind. 

As the stem enlarges, new rings of fibers may be form- 
ed, but always outside of the older ones. In hard stems 
of slow growth the rings are close together and chiefly 
consist of very firm wood-cells. In the soft stems of herbs 
the cell-tissue preponderates, and the ducts and cells of 
the vascular zones are delicate. The hardening of herba- 
ceous stems which takes place as they become mature, is 
due to the increase and induration of the wood-cells 
and ducts. 

The circular disposition of the fibers in the exogenous 
stem may be readily seen in a multitude of common 
plants. 

The potato tuber is a form of stem always accessible 
for observation. If a potato be cut across near the stem- 
end with a sharp knife, it is usually easy to identify upon 
the section a ring of vascular tissue, the general course of 
which is parallel to the circumference of the tuber except 
Avhere it runs out to the surface in the eyes or buds, and 
in the narrow stem at whose extremity it grows. If a 
slice across a potato be soaked in solution of iodine for a 
few minutes, the vascular rings become strikingly apparent. 
In its active cambial cells, albuminoids are abundant, which 
assume a yellow tinge with iodine. The starch of the cell- 
tissue, on the other hand, becomes intensely blue, making 
the vascular tissue all the more evident. 

Since the structure of the root is quite similar to that 
of the stem, a section of the common beet as well as one 
of a branch from any tree of temperate latitudes may 
serve to illustrate the concentric arrangement of the 
vascular zones when they are multiplied in number. 



THE VEGETATIVE ORGANS OF PLAINTS. 275 

Pith is the cell-tissue of the center of the stem. In 
young stems it is charged with juices ; in older ones it often 
becomes dead and sapless. In many cases, especially when 
growth is active, it becomes broken and nearly obliterated, 
leaving a hollow stem, as in a raiik pea-vine, or clover- 
stalk, or in a hollow potato. In the potato tuber the pith- 
cells are occupied throughout with starch, although, as the 
coloration by iodine makes evident, the quantity of starch 
diminishes from the vascular zone towards the center of 
the tuber. 

The Rind^ which, at first, consists of mere epidermis, 
or short, thick-walled cells, overlying soft cellular tissue, 
becomes penetrated with cells of unusual length and te- 
nacity, which, from their position in the plant, are often 
termed hast-cells. These, together with ducts of various 
kinds, all united firmly by their sides, constitute the so- 
called hast-Jlhers^ which grow chiefly upon the interior of 
the rind, in close proximity to the wood. With their 
abundant development and with age, the rind becomes 
hark as it occurs on shrubs and trees. The bast-cells give 
to the bark its peculiar toughness, and cause it to come 
off the stem in long and pliant strips. 

Bast-mats are made by weaving together strips of the 
inner bark of the Linden (bass or bast-wood) tree ; and all 
the textile materials employed in making cloth and cord- 
age, with the exception of cotton, as flax,hemp, New Zea- 
land flax, etc., are bast-fibers. The leather-wood or moose- 
wood bark often employed for tying flour-bags, has bast- 
fibers of extraordinary tenacity. 

The external rind, like the interior pith, becomes sapless 
and dead in perennial plants, and after a longer or shorter 
period falls away. The outer bark of the grape separates 
in long shreds a year or two after its formation. On most 
forest trees the bark remains for several or many years. 
The expansion of the tree furrows the bark with numerous 



276 



HOW CROPS GROW. 



and deep longitudinal rifts, and it gradually decays or 
drops away exteriorly as the newer bark forms within. 

GorTc is one form which the epidermal cells assume on 
the stem of the cork oak, on the potato tuber, and many 
other plants. 

Pith Rays. — Those portions of the first-formed cell- 
tissue which were interposed between the young and orig- 
inally ununited wood-fibers remain, and connect the pith 
with the rind. In hard stems 
they become flattened by the 
pressure of the fibers, and are 
readily seen in most kinds of wood 
when split lengthwise. They are 
especially conspicuous in the oak 
and maple, and form what is com- 
monly known as the silver-grain. 
The botanist terms them pith-rays 
or medullary rays. 

Fig. 51 exhibits a section of a 
bit of wood of the Red Pine, 
[Firms picea,) magnified 200 di- 
ameters. The section is made 
tangential to the stem and length- 
wise of the. wood-cells, four of 
whicli are in part represented, h ; 
it cuts across the pith-rays, whose 
cell-structure and position in the wood are seen at m, n. 

Cambium of Exogens. — The growing part of the exog- 
enous stem is thus found between the wood and the bark, 
or rather between the fully formed wood and the mature 
bark. There is, in fact, no definite limit where wood ceases 
and bark begins, for they are connected by the cambial or 
formative tissue, from which, on the one hand, wood-fibers, 
and on the other, bast-fibers, or the tissues of the bark, 
rapidly develope. In the cambium, likewise, the pith-rays 




THE VEGETATIVE ORGANS OE PLANTS. 



277 



which connect the inner and outer parts of the stem, con- 
tinue their outward growth. 

In spring-time the new cells that form in the cambial 
region are very delicate and easily broken. For this rea- 
son the rind or bark may be stripped from the wood with- 
out difficulty. In autumn these cells become thickened 
and indurated, become, in fact, full-grown bast and wood- 
cells, so that to peel the bark off smoothly is impossible. 

Minute Structure ©f Exogenous Stems. — The accom- 
panying figure (52) will serve to convey an idea of the mi- 
nute structure of the elements of the exoajenous stem. It 




Fig. 53. 

exhibits a highly magnified section lengthwise^ through a 
young potato tuber. A^ 5, is the rind ; e, is the vascular 
ring; /*, the pith. The outer cells of the rind are convert- 
ed into corh. They have become empty of sap and are 
nearly impervious to air and moisture. This corky-layer, 
a,* constitutes the thin coat or skin that may be so readily 
peeled off from a boiled potato. Whenever a potato is 
superficially wounded, even in winter time, the exposed 
part heals over by the formation of cork-cells. The cell- 
tissue of the rind consists at its center, 5, of full-formed 
cells with delicate membranes which contain numerous 
and large starch grains. On either hand, as the rind ap- 



* The bracket, a, is much too long, and b is correspondingly too short in the 



cut. 



278 



now CEOPS GKOAV. 



j)roaclies the corky-layer or the vascular ring, the cells are 
smaller, and contain smaller starch grains ; either side of 
these are noticed cells containing no starch, but having 
nuclei^ c, y. These nucleated cells are capable of multi- 
jDlication, and they are situated Avhere the growth of tlio 
tuber takes place. The rind, which 
makes a large part of the flesh of the 
potato, increases in thickness by the 
formation of new cells within and with- 
out. Without, where it joins the corky 
skin, the latter likewise grows. Within, 
contiguous to the vascular zone, new 
ducts are formed. Jn a similar manner, 
the j)iih expands by formation of new 
cells, where it joins the vascular tissue. 
The latter consists, in our figure, of ring, 
y spiral, and dotted ducts, like those al- 
ready described as occurring in the 
maize-stalk. The delicate cambial cells, 
c, are in the region of mo£t active 
growth. At this point new cells rap- 
idly develope, those to the right, in the 
figure, remaining plain cells and becom- 
ing loosely filled w^ith starch ; those to 
the left developing new ducts. 

In the slender, overground potato- 
stem, as in all the stems of most agricul- 
tural plants, the same relation of parts 
is to be observed, although the vascular 
and woody tissues often preponderate. 
Wood-cells are especially abundant in 
those stems that need strength for the fulfilment of their 
oflaces, and in them, especially in those of our trees, the 
structure is commonly more complicated. 

Perforation of Wood- Cells in the Conifers.— In the 
wood of cone-bearing trees there are no proper ducts, such 



53. 



THE VEGETATIVE 0EGA:N-S OF PLANTS. 



279 



as have been described. To answer the purpose of air 
and sap-channels, the wood-cells which constitute the con- 
centric rings of the old wood are constructed in a special 
manner, being provided laterally with visible pores, through 
which the contents of one cell may pass directly into those 
of its neisrhbors. Fis:. 



53, _S, represents a por- 
tion of an isolated wood- 
cell of the Scotch Fir, 
(JPlnus sylvestris^ mag- 
nified 200 diameters. 
Upon it are seen nearly 
circular disks, a;, y, the 
structure of which, while 
the cell is young, is 
shown by a section 
through them length- 
wise. A exhibits such 
a section through the 
thickened walls of two 
contiguous and adhering 
cells, ic, in both A and 
-S, shows a cavity be- 
tween the two primary 
cell-walls ; y is the nar- 
row part of the chan- 
nel, that remains while 
the membrane thickens 
around it. This is seen 
in B^ y, as a pore or 
opening in the cell. In 
A it appears closed because the section passes a little to 
one side of the pore. 

In the next figure, (54,) representing a transverse sec- 
tion of the spring wood of the same tree magnified 300 
diameters, the structure and the gradual formation of 




Fis. 54. 



280 HOW CEOPS GEOTV. 

these pore disks is made evident. The section, likewise, 
gives an instructive illustration of the general character 
of the simplest kind of wood. J?, are the young cells of 
the rind ; C, is the cambium, where cell multiplication 
goes on ; W, is the wood, whose cells are more developed 
the older they are, i. e., the more distant from the cam- 
bium, as is seen from their figure and the thickness of 
their walls. At a is shown the disk in its earliest stage ; b 
and c exhibit it in a more advanced growth before it be- 
comes a pore, the original cell-wall being still in place. 
At d, in the finished wood-cells, the disk has become a 
pore, the primary membrane has been absorbed, and a free 
channel made between the two cells. The dotted lines at 
d lead out laterally to two concentric circles, which repre- 
sent the disk-pore seen flatwise, as in fig. 53. At e, the 
section passes through the new annual ring into the au- 
tumn wood of the preceding year. 

Sieve-cells or sieve-ducts. — The spiral, ring, and dotted 
ducts and porous wood-cells already noticed, appear only 
in the older parts of the vascular bundles, and although 
they are occupied with sap at times when the stem is sur- 
charged with water, they are ordinarily filled with air 
alone. The real transmission of the nutritive juices of the 
growing plant, so far as it goes on through actual tubes, is 
now admitted to proceed in an independent set of ducts, 
the so-called sieve-cells, which are usually near to, and 
originate from the cambium. These are extremely deli- 
cate, elongated cells, whose transverse or lateral walls are 
perfori^ted, sieve-fashion, (by absorption of the original 
membrane,) so as to establish direct communication from 
one to another, and this occurs while they are yet charged 
with juices and at a time when the other ducts are occu- 
pied with air alone. These sieve-ducts are believed to be 
the channels through which the matters organized in the 
foliage most abundantly pass in their downward move- 
ment to nourish the stem and root. Fig. 55 represents 



THE VEGETATIVE ORGANS OF PLANTS. 



2S1 



>^"/f: 



the sieve-cells in the overground stem of the potato ; A, 
B^ cross-section of parts of vascular bundle — A^ exterior 
j^art towards rind ; _S, interior portion next to pith — «, a 
cell-tissue inclosing j\, 

the smaller sieve- 
cells, A^ jS, which 
contain sap turbid 
with minute gran- 
ules ; 5, cambium 
cells \ c, wood-cells 
(which are absent in 
the potato tuber ;) d, 
ducts intermingled 
with wood-cells. C 
represents a section 
lengthwise of the 
sieve-ducts; and Z>, 
more highly magni- 
fied,exhibits the fine- 
ly perforated, trans- a 
verse partitions, 
through Avliich the 
liquid contents free- 
ly pass. 

Milk DiictSo— Be- 
sides the ducts al- 
ready described, 
there is, in many 
plants, a system of 
irregularly branched 
channels containing 
a milky juice, as in the sweet potato, dandelion, milk- 
weed, etc. These milk-ducts, together with many other 
details of stem-structure, are imperfectly understood, and 
require no further notice in this treatise. 

Herbaceous Stems.— Annual stems of the exoi^enous 




282 HOTT CROPS GEOW. 

kind, whose growth is entirely arrested by winter, consist 
usually of a single ring of woody tissue with interior 
pith and surrounding bark. Often, however, the zone of 
wood is thin, and possesses but little solidity, while the 
chief part of the stem is made up of cell-tissue, so that the 
stem is herbaceous. 

Woody Stems. — ^Perennial exogenous stems consist, in 
temperate climates, of a series of rings or zones, corre- 
sponding in number Avith that of the years during which 
their growth has been progressing. The stems of our 
shrubs and trees, especially after the first few years of 
growth, consist, for the most part, of woody tissue, the pro- 
portion of cell-tissue being very small. 

The annual cessation of growth which occurs at the 
approach of winter, is marked by the formation of smaller 
or finer wood-cells, as shown in fig, 54, while the vigorous 
renewal of activity in the cambium at spring-time is ex- 
hibited by the growth of larger cells, and in many kinds 
of wood in the production of ducts, which, as in the oak, 
are visible to the eye at the interior of the annual layers. 

Sap-wood and Heart-wood. — ^The living processes in 

perennial stems, while jDroceeding with most force in the 
cambium, are not confined to that locality, but go on to a 
considerable depth in the wood. Except at the cambial 
layer, however, these processes consist not in the forma- 
tion of new cells, nor the enlargement of those once form- 
ed — not properly in growth — but in the transmission of 
sap* and the deposition of organized matter on the interior 
of the wood-cells. In consequence of this deposition tlie 
inner or heart-wood of many of our forest trees becomes 
much denser in texture and more durable for industrial 
purposes. It then acquires a color diiferent from the outer 
or sap-wood (alburnum,) becomes brown in most cases, 
though it is yellow in the barberry and red in the red 
cedar. 



THE YEGETATIVE ORGANS OF PLANTS. 283 

The final result of the filling up of the cells of the heart- 
wood is to make this part of the stem almost or quite im- 
passable to sap, so that the interior wood may be removed 
by decay without disturbing the vigor of the tree. 

Passage of Sap through the Stem.— The stem, besides 
supporting the foliage, fliowers, and fruit, has also a most 
important office in admitting the passage upward to these 
organs, of the water and mineral matters which enter the 
plant by the roots. Similarly, it allows the downward 
transfer to the roots, of substances gathered by the foliage 
from the atmosphere. To this and other topics connected 
with the ascent and descent of the sap we shall hereafter 
recur. 

The stem constitutes the chief part by weight of many 
plants, especially of forest trees, and serves the most im- 
portant uses in agriculture, as well as in a thousand other 
industries. 

§3. 

LEAVES. 

These most important organs issue from the stem, are 
at first folded curiously together in the bud, and after- 
wards expand so as to present a great amount of surface 
to the air and hght. 

The leaf consists of a thin membrane of cell-tissue, ar- 
ranged upon a skeleton or net-work of fibers and ducts. 
It is directly connected with, and apparently proceeds 
from, the cambial-layer of the stem, of which it may, ac- 
cordingly, be considered an expansion. 

lu certain plants, as the cactus (prickly pear), there 
scarcely exist any leaves, or, if any occur, they do not 
diflfer, except in external form, from the stems. Many of 
these plants, above ground are in form, all stem, while in 
structure and function, they are all leaf. 



284 HOW CEOPS GEOW. 

In the grasses, althougli the stem and leaf are distinguish- 
able in shajDe, they are but little unlike in other external 
characters. 

In forest trees, we find the most obvious and striking 
differences between the stem and leaves. 

Green Color of Leaves. — ^A peculiarity most character- 
istic of the leaf, so long as it is in vigorous discharge of 
its proper vegetative activities, is the possession of a f)reen 
color. This color is also proper in most cases to the young 
bark of the stem, a fact farther indicating the connection 
between these parts, or rather demonstrating their identity 
of origin and function, for it is true, not only in the case 
of the cactuses, but also in that of all other young plants, 
that the green (young) stems perform, to some extent, the 
same ofiices as the leaves. 

The loss of green color that occurs in autumn, in case 
of the foliage of our deciduous trees, or on the maturing 
of the plant in case of the cereal grains, is connected with 
the cessation of growth and death of the leaf. 

There are plants whose folia2:e has a red, broTvn, white, or other than 
a green color duiing the period of active growth. Mnny of these are 
cultivated by florists for ornamental purposes. The cells of these color- 
ed leaves are by no means destitute of chlorophyll, as is shown by mi- 
croscopic examination, though this substance is associated with other 
coloring matters which mask its green tint. 

Structure of Leaves. — While in shape, size, modes of 
arrangement upon, and attachment to the stem, we find 
among leaves no end of diversity, there is great simplicity 
in the matter of then* internal structure. 

The whole surface of the leaf, on both sides, is covered 
with epidermis., a coating, which, in many cases, may be 
readily stripped off the leaf, and consists of thick- walled 
cells, which are, for the most part, devoid of liquid con- 
tents, except when very young. {E^ JS, fig. 56.) 

The accompanying figure (56) represents the appearance of a bit of 
bean-leaf as seen on a section from the upper to the lower surface and 
highly magnified. 



THE VEGETATIVE ORGANS OP PLANTS. 



285 



Below the upper epidermis, there often occur one or 
more layers of oblong cells, whose sides are in close con- 
tact, and which are arranged endwise, with reference to 
the flat of the leaf. Below these, down to the lower epi- 
dermis, for one-half to three-quarters of the thickness of 
the leaf, the cells are commonly spherical or irregular in 
figure and arrangement, and more loosely disposed, with 
numerous and large interspaces. 

The interspaces among the leaf-cells are occupied with air, 
which is also, in most cases, the only con- 
tent of the epidermal cells. The active 
cells of the leaf contain some or all of the 
various proximate principles which have 
been already noticed, and in addition 
the coloring matter of vegetation, — the 
so-called chlorophyll^ or leaf-green, p. 
109. Under the microscope, this sub- 
stance is commonly seen in the form 
of minute grains attached to the walls 
of the cells, as in fig. 56, or coating 
starch granules, or else floating free in 
the cell-sap. 

The structure of the veins or ribs of the leaf is similar 
to that of the vascular bundles or fibers of the stem, of 
which they are branches. At «, fig. 56, is seen the cross 
section of a vein in the bean-leaf. 

The epidermis^ while often smooth, is frequently beset 
with hairs or glands, as seen in the figure. These are va- 
riously shaped cells, sometimes empty, sometimes, as in 
the nettle, filled with an acid liquid. Their office is little 
understood. 

Leaf-Pores. — The epidermis is further provided Avith a 
vast number of curious " breathing pores," or stomata, by 
means of which the intercellular spaces in the interior of 
the leaf may be brought into direct communication with 
the outer atmosphere. Each of these stomata consists 




286 



HOW CROPS GBOW. 




Fiff. 57. 



usually of two curved cells, which are disposed toward 
each other nearly like the two sides of the letter O, or like 
the halves of an elliptical carriage-spring, (figs. 52 and 53). 

The opening between them 
is an actual orifice in the 
skin of the leaf. The size of 
the orifice is, however, con- 
stantly changing, as the at- 
mosphere becomes drier or 
more moist, and as the sun- 
light acts more or less in- 
tensely on its surface. In 
moist air, they curve out- 
wards, and the aperture is 
enlarged ; in dry air, they straighten and shut together 
like the springs of a heavily loaded carriage, and nearly 
or entirely close the entrance. The efiect of strong light 
is to enlarge their orifices. 

In fi^. 56 is represented a section tlirougli tlie sliorter diameter of a 
pore on the under surface of a bean-leaf The air-space within it is 
shaded blaclc. Unlike tlie other epidermal cells, those of the leaf-pore 
contain grains of chlorophyll. 

Fig. 57 represents a portion of the epidermis of the upper surface of 
a potato-leaf, and fig. 58 a similar portion of the under surface of the same 
leaf, magnified 200 diameters. In both figures arc seen the open pores 
between the semi-elliptical cells. The outline of the other epidermal 
cells is marked by irregular double lines. 
The round bodies in the cells of the 
pores are starch-grains, often present 
in these cells, when not existing in any 
other part of the leaf. 

The stomata are with few ex- 
ceptions altogether wanting on 
the submerged leaves of aquatic 
plants. On floating leaves they 
occur, but only on the upper 
surface. Thus, as a rule, they 
are not found in contact with liquid water. On the other 
hand, they are either absent from, or comparatively few in 




'"=?€€? 



Fig. 58, 



THE VEGETATIVE ORGANS OF PLANTS. 287 

number upon, the upper surfaces of land plants, wliicL. are 
exposed to the heat of the sun, while they exist in great 
numbers on the lower sides of all green leaves. In number 
and size, they vary remarkably. Some leaves possess but 
800 to the square inch, while others have as many as 
170,000 to that amount of surface. About 100,000 may 
be counted on an average-sized apple-leaf. In general, 
they are largest and most numerous on plants which be- 
long in damp and shaded situations, and then exist on 
both sides of the leaf. 

The epidermis itself is most dense — consists of thick- 
walled cells and several layers of them — in case of leaves 
which belong to the vegetation of sandy soils in hot cli- 
mates. Often it is impregnated with wax on its upper 
surface, and is tliereby made almost impenetrable to moist- 
ure. On the other hand, in rapidly growing plants adapt- 
ed to moist situations, the epidermis is thin and delicate. 

Exhalation of Water- Vapor. — A considerable loss of 
water goes on from the leaves of growing plants when 
they are freely exposed to the atmosphere. The water 
thus lost exhales in the form of invisible vapor. The 
quantity of water exhaled from any plant may be easily 
ascertained, provided it is growing in a pot of glazed 
earthen, or other impervious material. A metal or glass 
cover is cemented air-tight to the rim of the vessel, and 
around the stem of the plant. The cover has an opening 
with a cork, through which weighed quantities of water 
are added from time to time, as required. The amount 
of exhalation during any given interval of time is learned 
with a close approach to accuracy by simply noting the 
loss of weight which the plant and pot together suffer. 
Hales, who first experimented in this manner, found that 
a sunflower, whose foliage had an aggregate surface of 
39 square feet, gave off 3 lbs. of water in a space of 24 
hours. Knop observed a maize-plant to exhale, between 



288 HOW CEOPS GEOW. 

May 22d and September 4th, no less than 36 times its 
weight of water. 

Exhalation is not a regular or uniform jjrocess, but varies 
with a number of circumstances and conditions. It de- 
pends largely upon the dryness and temperature of the 
air. When the air is in the state most favorable to 
evaporation, the loss from the plant is rapid and large. 
When the air is saturated with moisture, as during dewy 
nights or rainy weather, then exhalation is nearly or 
totally checked. 

The temperature of the soil, and even its chemical com- 
position, the condition of the leaf as to its age, texture, 
and number of stomata, likewise affect the rate of ex- 
halation. 

Exhalation is a process not necessary to the life of the 
plant, since it may be suppressed or be reduced to a 
minimum, as in a Wardian case or fernery, without evident 
influence on growth. IsTeither is it detrimental, unless the 
loss is greater than the supply. If water escapes from the 
leaves faster than it enters the roots, the plant wilts ; and 
if this disturbance goes on too for, it dies. 

Exhalation ordinarily proceeds to a large extent from 
the surface of the epidermal cells. Although the cavities 
of these cells are chiefly occupied with air, their thickened 
walls transmit outward the water which is supplied to 
the interior of the leaf through the cambial ducts. Other- 
wise the escape of vapor occurs through the stomata. These 
pores appear to have the function of regulating the exhala- 
tion, to a great extent, by their property of closing, when 
the air, from its dryness, favors rapid evaporation. They 
are, in fact, self-acting valves which protect the plant from 
too sudden and rapid loss of water. 

Access of Air to the Interior of the Plant. — Not only 
does the leaf allow the escape of vapor of water, but it 
admits of the entrance and exit of gaseous bodies. 



THE VEGETATIVE OEGAISTS OF PLAISTTS. 



289 



The particles of atmospheric air have easy access to the 
interior of all leaves, however dense and close their epi- 
dermis may be, however few or small their stomata. All 
leaves are actively engaged in absorbing and exhaling cer- 
tain gaseous ingredients of the atmosphere during the 
whole of their healthy existence. 

The entire plant is, in fact, pervious to air through the 
stomata of the leaves. These com- 
municate with the intercellular 
spaces of the leaf, whicb are, in 
general, occupied exclusively with 
air, and these again connect with 
the ducts which ramify throughout 
the veins of the leaf and branch 
from the vascular bundles of the 
stem. In the bark or epidermis of 
woody stems, as Hales long ago 
discovered, pores or cracks exist, 
through which the air has communi- 
cation with the longitudinal ducts. 

These facts admit of demonstration by 
simple means, Sachs employs for this pur- 
pose an apparatus consisting of a short wide 
tube of glass, B^ fig. 59, to which is adapted, 
below, by a tightly fitting cork, a bent glass 
tube. The stem of a leaf is passed through 
a cork which is then secured air-tight in the 
other opening of the wide tube, the leaf itself 
being included in the latter, and the joints 
are made air-tight by smearing with tallow. 
The whole is then placed in a glass jar con- 
taining enough water to cover the projecting leaf-stem, and mercury is 
quickly poured into the open end of the bent tube, so as nearly to fill the 
latter. The pressure of the column of this dense liquid immediately forces 
air into the stomata of the leaf, and a corresponding quantity is forced on 
through the intercellular spaces and through the vein-ducts into the 
ducts of the leaf-stem, whence it issues in fine bubbles at S. It is even 
easy in many cases to demonstrate the permeability of the leaf to air by 
immersing it in water, and, taking the leaf-stem between the lips, produce 
a current by blowing. In this case the air escapes from the stomata. 

The air-passages of the stem may be shown by a similar arrangement, 
13 




290 HOW CEOPS GROW. 

or in many instances, as, for example, with a stalk of maize, by simply 
immersing one end in water and blowing into the other. 

On the contrary, roots are destitute of any visible 
pores, and are not pervious to external air or vapor in the 
sense that leaves and young stems are. 

The air passages in the plant correspond roughly to the 
mouth, throat, and breathing cavities of the animal. We 
have, as yet, merely noticed the direct communication of 
these passages with the external air by means of micros- 
copically visible openings. But the cells which are not 
visibly porous readily allow the access and egress of wa- 
ter and of gases by osmose. To the mode in which this 
is effected we shall recur on subsequent pages, (pp. 354- 
366.) 

The Offices of Foliage are to put the plant in commu- 
nication with the atmosphere and with the sun. On the 
one hand it permits, and to a certain degree regulates, the 
escape of the water which is continually pumped into the 
plant by its roots, and on the other hand it absorbs from 
the air, which freely penetrates it, certain gases which 
furnish the principal materials for the organization of vege- 
table matter. • We have seen that the plant consists of 
elements, some of which are volatile at the heat of ordina- 
ry fires, while others are fixed at this temperature. When 
a plant is burned, the former, to the extent of 90-99 per 
cent of the plant, are converted into gases, the latter re- 
main as ashes. 

The reconstruction of vegetation from the products of 
its combustion (or decay) is, in its simplest phase, the 
gathering by a new plant of the ashes from the soil 
through its roots, and of these gases from the air by its 
leaves, and the compounding of these comparatively sim- 
ple substances into the highly complex ingredients of the 
vegetable organism. Of this work the leaves have by far 
the larger share to perform ; hence the extent of their sur- 
face and their indispensability to the welfare of the plant. 



EEPEODUCTTVE OEGAN-S OF PLANTS. 291 

The assimilation of carbon in the plant is most inti- 
mately connected with the chlorophyll, which has been no- 
ticed as the green coloring matter of the leaf, and depends 
also upon the solar rays. 



CHAPTER IV. 
KEPEODUCTIVE ORGANS OF PLANTS. 

§1. 

THE FLOWER. 

The onward growth of the stem or of its branches is 
not necessarily limited, until from the terminal buds, in- 
stead of leaves, only Flowers unfold. When this happens, 
as is the case with most annual tmd biennial plants, raised 
on the farm or in the garden, the vegetative energy has usu- 
ally attained its fullest development, and the reproductive 
function begins to prepare for the death of the individual 
by providing seeds which shall perpetuate the species. 

There is often at first no apparent difference between 
the leaf-buds and flower-buds, but commonly in the later 
stages of their growth, the latter are to be readily dis- 
tinguished from the former by their greater size, and by 
peculiar shape or color. 

The Flower is a short branch, bearing a collection of 
organs, which, though usually having little resemblance 
to foliage, may be considered as leaves, more or less mod- 
ified in form, color, and office. 

The flower commonly presents four different sets of or- 
gans, viz.. Calyx, Corolla, Stamens, and Pistils, and is 
then said to be complete, as in case of the apple, potato, 



292 



HOW CROPS GROW. 



and many common plants. Fig. 60 represents the com- 
plete flower of the Fuchsia, or ladies' ear-drop, now uni- 
versally cultivated. In fig. 61 the same is shown in 
section. 

The Calyx, (cup,) ex, is the outermost floral envelope. 
Its color is red or white in the Fuchsia, though generally 
it is green. When it consists of several distinct leaves, 
they are called 
sepals. The calyx 
is frequently small 
and inconspicuous. 
In some cases it 
falls away as the 
flower opens. In 
the Fuchsia it firm- 
ly adheres at its 
base to the seed- 
vessel, and is divid- 
' ed into four lobes. 

The Corolla, 

(crown,) c, or ca, 

is one or several 

series of leaves 

which are situated 

within the. calyx. 
It is usually of some other than a green color, (in the Fuchsia, 
purple, etc.,) often has marked peculiarities of form and 
great delicacy of structure, and thus chiefly gives beauty 
to the flower. When the corolla is divided into separate 
leaves, these are termed petals. The Fuchsia, has four 
petals, which are attached to the calyx-tube. 

The Stamens,^, in fig's 60 and 61, are generally slender, 
thread-like organs, terminated by an oblong sack, the an- 
ther, which, when the flower attains its full growth, dis- 
charges a fine yellow or brown dust, the so-called pollen. 





Fig. eo. 



Fig. 61. 



ElEPBODTTCTIVE ORGATS^S OF PLANTS. 293 

The forms of anthers, as -well as of the grains of pollen, vary with nearly 
every kind of plant. The yellow pollen of pine and spruce trees is not 
infrequently transported by the wind to a great distance, and when 
brought down by rain in considerable quantities, has been mistaken for 
sulphur. 

The Pistil, j(?, in fig's 60 and 61, or pistils, occupy the 
center of the perfect flower. They are exceedingly va- 
rious in form, but always have at their base the seed-ves- 
sels or ovaries^ ou, in which are found the ovules (little 
eggs) or rudimentary seeds. The summit of the pistil is 
destitute of the epidermis which covers all other parts of 
the plant, and is termed the stigma, st. 

As has been remarked, the floral organs may be consid- 
ered to be modified leaves ; or rather, all the appendages 
of the stem — the leaves and the parts of the flower to- 
gether — are different developments of one fundamental 
organ. 

The justness of this idea is sustained by the transforma- 
tions which are often observed. 

The rose in its natural state has a corolla consisting of 
five pe'tals, but has a multitude of stamens and pistils. In 
a rich soil, or as the effect of those agencies which are 
united in " cultivation," nearly all the pistils and stamens 
lose their reproductive function and proper structure, and 
revert to petals ; hence the flower becomes double. The 
tulip, poppy, and numerous garden-flowers, illustrate this 
interesting metamorphosis, and in these flowers we may 
often see at once the change in various stages intermediate 
between the perfect petal and the unaltered pistil. 

On the other hand, the reversion of all the floral organs 
into ordinary green leaves has been observed not infre- 
quently, in case of the rose, white clover, and other 
plants. 

While the complete flower consists of the four sets of 
organs abqve described, only the stamens and pistils are 
essential to the production of seed. The latter, accord- 



294 HOW CEOPS GBOW. 

ingly, constitute a perfect flower even in the absence of 
calyx and corolla. 

The flower of buckwheat has no corolla, but a white or 
pinkish calyx. 

The grasses have flowers in w^hich calyx and corolla are 
represented by scale-like leaves, which, as the plants ma- 
ture, become chaff. 

In various plants the stamens and pistils are borne in 
separate flowers. Such are called monoecious plants, of 
which the birch and oak, maize, melon, squash, cucumber, 
and oftentimes the strawberry, are examples. 

In case of maize, the staminate flowers are the " tas- 
sels " at the summit of the stalk ; the pistillate flowers 
are the young ears, the pistils themselves being the " silk," 
each fiber of which has an ovary at its base, that, if fer- 
tilized, developes to a kernel. 

Dioecious plants are those which bear the staminate 
(male, or sterile) flowers and the pistillate (female, or fer- 
tile) flowers on different individuals ; the willow tree, the 
hop-vine, and hemp, are of this kind. 

Fertilization and Fructification. — ^The grand function 
of the flower is fructification. For this purpose the pollen 
must fall upon or be carried by wind, insects, or other agen- 
cies, to the naked tip of the pistil. Thus situated, each 
pollen-grain sends out a slender tube of microscopic diam- 
eter, which penetrates the interior of the pistil until it en- 
ters the seed-sack and comes in contact with the ovule or 
rudimentary seed. This contact being established, the 
ovule is fertilized and begins to grow. Thenceforward 
the corolla and stamens usually wither, while the base of 
the pistil and the included ovules rapidly increase in size 
until the seeds are ripe, when the seed-vessel falls to the 
ground or else opens and releases its contents. 

Fig. 62 exhibits the process of fertilization as observed 
in a plant allied to buckwheat, viz., the Polygonum con- 



REPRODUCTIYE ORGANS OF PLANTS. 



295 



volvulus. The cut represents a magnified section length- 
wise through the short pistil ; a, is the stigma or summit 
of the pistil; h, are grains of pollen; c, are pollen tubes 
that have penetrated^into the seed- 
vessel which forms the base of the 
pistil ; one has entered the mouth of 
tlie rudimentary seed, ^, and reached 
tlie embryo sack, e, within which it 
causes the development of a germ ; d, 
represents the interior wall of the 
seed-vessel ; A, the base of the seed 
and its attachment to the seed-vessel. 

Darwin has shown that certain 
plants, which have pistils and stamens 
in the same flower, are incapable of 
self-fertilization, and depend upon in- 
sects to carry pollen to their stigmas. 
Such are many Orchids. 

Artificial Fecundation has been 
proposed by Hooibrenk, in Belgium, ^ ^^^- ^^• 
as a means of increasing the yield of certain crops. Hooi- 
brenk's plan of agitating the heads of grain at the time 
when the pollen is ripe, in order to ensure its distribution, 
which is done by two men traversing the field carrying a 
rope between them so as to lightly brush over the heads, 
appears to have been found very useful in some cases, 
though in many trials no good effects have followed its 
application. We must therefore conclude that agitation 
by the winds and the good ofiices of insects commonly 
render artificial assistance in the fecundating process en- 
tirely superfluous. 

Hybridizing. — As the union of the sexes of different 
kinds of animals sometimes results in the birth of a hybrid, 
so among plants, the ovules of one kind may be fertilized 
by the pollen of another, and the seed thus developed, in 
its growth, produces a hybrid plant. In both the animal 




296 HOW CROPS GEOW. 

and vegetable kingdoms the limits within which hybridiza- 
tion is possible appear to be very, narrow. It is only be- 
tween closely allied species that fecundation can take place. 
Wheat, oats, and barley, show no tendency to " mix " ; the 
pollen of one of these similar plants being incapable of 
fertilizing the ovules of the others. 

In flower and fruit-culture, hybridization is practised or 
attempted, as a means of producing new kinds. Thus the 
celebrated Rogers' Seedling Grapes are believed to be hy- 
brids between the European grape, Yitis vinifera^ and 
the allied but distinct Yitis lahriisca^ of North America. 

Hybridization between plants is effected, if at all, by 
removing from the flower of one kind, the stamens before 
they shed their pollen, and dusting the summit of the pistil 
with pollen from another kind. 

The mixing of different varieties, as commonly happens 
among maize, melons, etc., is not properly hybridization, 
this word being used in the long-established sense. We 
are thus led to brief notice of the meaning of the terms 
species and variety, and of the distinctions employed in 
botanical classification. 

Species. — ^The idea of species as distinct from variety 
which has been held by most scientific authorities hither- 
to, is based primarily on the faculty of continued repro- 
duction. The horse is a species comprising many vari- 
eties. Any two of these varieties by sexual union may 
propagate the species. The same is true of the ass. The 
horse and the ass by sexual union produce a hybrid — ^the 
mule, — ^but the sexual union of mules is without result. 
They cannot continue the mule as a distinct kind of ani- 
mal — as a species. Among animals a species therefore com- 
prises all those individuals which are related by common 
origin or fraternity, and which are capable of sexual fer- 
tility. This conception involves original and permanent 
differences between different species. 



KEPRODUCTIYE OEGAIfS OF PLANTS. 297 

Species, therefore, cannot change any of their essential 
characters, those characters which are hence termed specific. 

Varieties. — Individuals of the same species differ. In 
fact, no two individuals are quite alike. Circumstances of 
temperature, food, and habits of life, increase these differ- 
ences, and varieties originate when such differences assume 
a comparative permanence and fixity. But as external 
conditions cause variation away from any particular rep- 
resentative of a species, so they may cause variation back 
again to the original, and although variation may take a 
seemingly wide range, its bounds are fixed and do not 
touch specific characters. 

The causes that produce varieties are numerous, but in 
many cases their nature and their mode of action is diflS- 
cult or impossible to understand. The influence of scarcity 
or abundance of nutriment we can easily comprehend may 
dwarf a plant or lead to the production of a giant indi- 
vidual; but how, in some cases, the peculiarities thus im- 
pressed upon individuals acquire permanence and are 
transmitted to subsequent generations, while in others 
they disappear, is beyond explanation. 

Among plants, varieties may often be perpetuated by 
the seed. This is true of our cereal and leguminous 
plants, which reproduce their kind with striking regulari- 
ty. Other plants cannot be or are not reproduced unalter- 
ed by the seed, but are continued in the possession of their 
peculiarities by cuttings, layers, and grafts. Here the in- 
dividual plant is in a sense divided and multiplied. The 
species is propagated, but not reproduced. The fact that 
the seeds of a potato, a grape, an apple, or pear, cannot be 
depended upon to reproduce the variety, may perhaps be 
more commonly due to unavoidable contact of pollen 
from other varieties, than to inability of the mother plant 
to perpetuate its peculiarities. That such inability often 
exists, is, however, well established, and is, in general, 
most obvious in case of varieties that have to the greatest 
13* 



298 HOW CROPS GROW. 

degree departed from the original specific type. Thus 
nature puts the same limit to variation within a species 
that she has established against the mixing of species. 

Darwin's Hypothesis, which is now accepted by many 
naturalists, is to the effect that species, as above defined, 
do not exist, but that new kinds (so-called species) of ani- 
mals and plants may arise by variation, and that all exist- 
ing animals and plants may have developed by a process 
of " natural selection " from one original type. Our ob- 
ject here is not to discuss this intricate question, but sim- 
ply to put the reader in possession of the meaning attach- 
ed to the terms currently employed in science — terms 
which must long continue in use and which are necessarily 
found in these pages.* 

Genus, (plural Genera.) — In the language of anti-Dar- 
winianism, any set of oaks that are capable of reproducing 
their kind by seed, but cannot mix their seed with other 
oaks, constitute a species. Thus, the white oak is one 
species, the red oak is another, the water oak is a third, 
the live oak a fourth, and so on. All the oaks, white, red, 
etc., taken together, form a group which has a series of 
characters in common that distinguishes them from all other 
trees and plants. Such a group of species is called a genus. 

Families or Orders, in botanical language, are groups 
of genera that agree in certain particulars. Thus the sev- 
eral plants well-known as mallows, hollyhock, okra, aiid 
cotton, are representatives of as many different genera. 
They all agree in a number of points, especially as regards 
the structure of their fruit. They are accordingly group- 
ed together into a natural family or order, which differs 
from all others. 

Classes, Series, and Classification. — Classes are groups 

* For a masterly statement of the facts and evidence bearing on these points, 
which are of the greatest importance to the agricultarist, see Darwin's works 
" On the Origin of Species," and " On the Variation of Animals and Plants 
under Domestication." 



REPKODUCTIVE OEGAN-S OF PLANTS. 299 

of orders, and Series are groups of classes. In botanical 
classification as now universally employed — classification 
after the JSTatural System — all plants are separated into 
two series, as follows : 

1. Flowering Plants {Phcenogams) which produce 
flowers and seeds with embryos, and 

2. Flowerless Plants ( Cryptogams) that have no proper 
flowers, and are reproduced by spores which are in most 
cases single cells. This series includes Ferns, Horse-tails, 
Mosses, Liverworts, Lichens, Sea-weeds, Mushrooms, and 
Molds. 

The use of classification is to give precision to our no- 
tions and distinctions, and to facilitate the using and ac- 
quisition of knowledge. Series, classes, orders, genera, 
species, and varieties, are as valuable to the naturalist as 
pigeon holes are to the accountant, or shelves and draw- 
ers to the merchant. 

Botanical Nomenclature. — So, too, the Latin or Greek 
names which botanists employ are essential for the discrim- 
ination of plants, being equally received in all countries, 
and belonging to all languages where science has a home.. 
They are made necessary not only by the confusion of 
tongues, but by confusions in each vernacular. 

Botanical usage requires for each plant two names, one 
to specify the genus, another to indicate the species. 
Thus all oaks are designated by the Latin word Quercus, 
while the red oak is Quercus rubra, the white oak is 
Quercus alba, the live oak is Quercus virens, etc. 

The designation of certain important families of plants 
is derived from a peculiarity in the form or arrangement 
of the flower. Thus the pulse family, comprising the 
bean, pea, and vetch, as well as lucern and clover, are 
called Papilionaceous plants, from the resemblance of 
their flowers to a butterfly, (Latin, ^a^^7^o). Again, the 
mustard family, including the radish, turnip, cabbage, wa- 



300 HOW CROPS GROW. 

ter-cress, etc., are termed Cruciferous plants, because their 
flowers have four petals arranged like the four arms of a 
cross, (Latin, crux). 

The flowers of a large natural order of plants are ar- 
ranged side by side, often in great numbers, on the expand- 
ed extremity of the flower-stem. Examples are the thistle, 
dandelion, sun-flower, artichoke, China-aster, etc., which, 
from bearing such compound heads, are called Composite 
plants. 

The Coniferous (cone-bearing) plants comprise the 
pines, larches, hemlocks, etc., whose flowers are arranged 
in conical receptacles. 

The flowers of the carrot, parsnip, and caraway, are ar- 
ranged at the extremities of stalks which radiate from a 
central stem like the arms of an umbrella ; hence they are 
called ZPmhelliferous plants, (from umhel^ Latin, for little 
screen). 



THE FRUIT 

The Frfit comprises the seed-vessel and the seed, to- 
gether with their various appendages. 

The Seed-vessel, consisting of the base of the pistil in 
its matured state, exhibits a great variety of forms and 
characters, which serve, chiefly, to define the different 
kinds of Fruits. Of these we shall only adduce such as 
are of common occurrence and belong to the farm. 

The IVut has a hard, leathery or bony shell, that does 
not open spontaneously. Examples are the acorn, chest- 
nut, beech-nut, and hazel-nut. The cup of the acorn and 
the bur of the others is a sort of fleshy calyx. 

The Stone-fruit or Drupe is a nut enveloped by a 
fleshy or leathery coating, like the peach, cherry, and plum, 



REPRODUCTIVE ORGANS OF PLANTS. 301 

also the butternut and hickory-nut. Raspberries and 
blackberries are clusters of small drupes. 

Pome is a term applied to fruits like the apple and 
pear, the core of which is the true seed-vessel, originally 
belonging to the pistil, while the often edible flesh is the 
enormously enlarged and thickened calyx, whose withered 
tips are always to be found at the end opposite the stem. 

The Berry is a many-seeded fruit of which the entire 
seed-vessel becomes thick and soft, as the grape, currant, 
tomato, and huckleberry. 

Gourd fruits have externally a hard rind, but are fleshy 
in the interior. The melon, squash, and cucumber, are of 
this kind. 

The Akene is a fruit containing a single seed which does 
not separate from its dry envelope. The so-called seeds 
of the composite plants, for example the sun-flower, thistle, 
and dandelion, are aJcenes. On removing the outer husk 
or seed-vessel we find within the true seed. Many akenes 
are furnished with Si. pappus, a downy or hairy appendage, 
as seen in the thistle, which enables the seed to float and 
be carried about in the wind. The fruit or grain of buck- 
wheat is akene-like. 

The Grains are properly fruits. Wheat and maize con- 
sist of the seed and the seed-vessel closely united. When 
these grains are ground, the bran that comes off is the 
seed-vessel together with the outer coatings of the seed. 
Barley-grain, in addition to the seed-vessel, has the petals 
of the flower or inner chafi*, and oats have, besides these, 
the calyx or outer chafl" adhering to the seed. 

Pod is the name properly applied to any dry seed-ves- 
sel which opens and scatters its seeds when ripe. Several 
kinds have received special designations ; of these we need 
only notice one. 

The Legume is a pod, like that of the bean, which 
splits into two halves, along whose inner edges seeds are 



302 HOW CEOPS GROW. 

borne. The pulse family, or papilionaceous plants, are also 
termed leguminous from the form of their fruit. 

The Seed, or ripened ovule, is borne on a stalk which 
connects it with the seed-vessel. Through this stalk it is 
supplied with nutriment while growing. When matured 
and detached, a scar commonly indicates the point of 
former connection. 

The seed has usually two distinct coats or integuments. 
The outer one is often hard, and is generally smooth. In 
the case of cotton-seed it is covered with the valuable cot- 
ton fiber. The second coat is commonly thin and delicate. 

. The Kernel lies within the integuments. In many cases 
it consists exclusively of the embryo, or rudimentary 
plant. In others it contains, besides the embryo, what has 
received the name of endosperm. 

The Endosperm forms the chief bulk of all the grains. If 
we cut a seed of maize in two lengthwise, we observe ex- 
tending from the point where it was attached to the cob 
the soft " chit," J, fig. 63, which is the embryo, to be pres- 
ently noticed. The remainder of the kernel, a, is endo- 
sperm; the latter, therefore, yields in great part the 
flour or meal w^hich is so important a part of the food of 
man and animals. 

The endosperm is intended for the support of the young 
j)lant as it developes from the embryo, before it is capable 
of depending on the soil and atmosphere for sustenance. 
It is not, however, an indispensable part of the seed, and 
may be entirely removed from it, without thereby prevent- 
ing the growth of a new plant. 

The Emhryo or Germ is the essential and most import- 
ant portion of the seed. It is, in fact, a ready-formed 
plant in miniature, and has its root, stem, leaves, ^nd a 
bud, although these organs are often as undeveloped in 
form as they are in size. 

As above mentioned, the chit of the seeds of maize and 



EEPRODTJCTIVE ORGANS OF PLANTS. 303 

the other grains is the embryo. Its form is with difficulty 
distinguishable in the dry seeds, but when they have been 
soaked for several days in water, it is readily removed 
from the accompanying endosperm, and plainly exhibits 
its three parts, viz., the radicle^ the plumule^ and the 
cotyledon. 

In fig. 63 is represented the embryo of maize. In A 
and B it is seen in section imbedded in the endosperm. 
C exhibits the detached embryo. The Radicle^ r, is the 
rootlet of the seed-plant, or rather the point from which 
downward growth proceeds, from which the first true roots 
are produced. The Plumule^ c, is the ascending axis of 
the plant, the central bud, out of which the stem with new 
leaves, flowers, etc., is developed. The Cotyledon^ h, is 
in structure a ready-formed leaf, which clasps the plumule 
in the embryo, as the 
proper leaves clasp the 
stem in the mature 
maize-plant. The coty- 
ledon of maize does not, 
however, perform the 
functions of a leaf; on 

the contrary, it remains in the soil during the act of sprout- 
ing, and its contents, like those of the endosperm, are 
absorbed by the plumule and radicle. The leaves which 
appear above-ground, in the case of maize and the other 
grains (buckwheat excepted,) are those which in the 
embryo were wrapped together in the plumule, where they 
can be plainly distinguished by the aid of .a magnifier. 

It will be noticed that the true grains (which have 
sheathing leaves and hollow jointed stems) are monocot- 
yledonous (one-cotyledoned) in the seed. As has been 
mentioned, this is characteristic of plants with Endogenous 
or inside-growing stems, (p. 268.) 

The seeds of the Exogens (outside-growers) (p. 273) are 
dicotyledonous^ i. e., have two cotyledons. Those of 




304 HOW CROPS GEOW. 

buckwheat, flax, and tobacco, contain an endosperm. The 
seeds of nearly all other exogenous agricultural plants are 
destitute of an endosperm, and, exclusive of the coats, 
consist entirely of embryo. Such are the seeds of the Le- 
guminosae, viz., the bean, pea, and clover ; of the Crucif- 
erae, viz., turnip, radish, and cabbage ; of ordinary fruits, 
the apple, pear, cherry, plum, and peach ; of the gourd 
family, viz., the pumpkin, melon and cucumber ; and finally 
of many hard-wooded trees, viz., the oak, maple, elm, 
birch, and beech. 

We may best observe the structure of the two-cotyle- 
doned embryo in the garden or kidney-bean. After a bean 
has been soaked in warm Avater for several hours, the coats 
may be easily removed, and the two fleshy cotyledons, c, 
c, in fig. 64, are found divided from each other save at the 
point where the radicle, a, is seen projecting like a blunt 
spur. On carefully breaking away 
one of the cotyledons, we get a side 
view of the radicle, a, and plumule,^, 
the former of which was partially and 
the latter entirely imbedded between 
the cotyledons. The plumule plainly 
Fig. 64. exhibits two delicate leaves, on which 

the unaided eye may note the veins. These leaves are 
folded together along their mid-ribs, and may be opened 
and spread out with help of a needle. 

When the kidney-bean {Phaseolus) germinates, the cot- 
yledons are carried up into the air, where they become 
green and constitute the first pair of leaves of the new 
plant. The second pair are the tiny leaves of the plumule 
just described, between which is the bud, whence all the 
subsequent aerial organs develope in succession. 

In the horse-bean, (J^5«), as in the pea, the cotyledons 
never assume the office of leaves, but remain in the soil and 
gradually yield a large share of their contents to the 




EEPEODUCTIVE OEGANS OF PLANTS. 305 

growing plant, shriveling and shrinking greatly in bulk, 
and finally falling away and passing into decay. 

§ 3. 

VITALITY OF SEEDS AND THEIR INFLUENCE ON THE 
PLANTS THEY PRODUCE. 

Dnration of Vitality. — In the mature seed when kept 
from excess of moisture, the embryo lies dormant. The 
duration of its vitality is very various. The seeds of the 
willow, it is asserted, will not grow after having once be- 
come dry, but must be sown when fresh ; they lose their 
germinative power in two weeks after ripening. 

With regard to the duration of the vitality of the 
seeds of agricultural plants there is no little conflict of 
opinion among those who have experimented with them. 

The leguminous seeds appear to remain capable of 
germination during long periods. Girardin sprouted beans 
that were over a century old. It is said that Grimstone 
with great pains raised peas from a seed taken from a 
sealed vase found in the sarcophagus of an Egyptian mum- 
my, presented to the British Museum by Sir G. Wilkinson, 
and estimated to be near 3,000 years old. 

The seeds of wheat usually lose their power of growth 
after having been kept 3-7 years. Count Sternberg and 
others are said to have succeeded in germinating wheat 
taken from an Egyptian mummy, but only after soaking 
it in oil. Sternberg relates that this ancient wheat mani- 
fested no vitality when placed in the soil under ordinary 
circumstances, nor even when submitted to the action of 
acids or other substances which gardeners sometimes em- 
ploy to promote sprouting. Yilmorin, from his own trials, 
doubts altogether the authenticity of the " mummy wheat." 

Dietrich, {Hoff. Jahr.^ 1862-3, p. 77,) experimented 
with seeds of wheat, rye, and a species of 3romus, which 



306 HOW CEOPS GEOW. 

were 185 years old. IsTearly every means reputed to 
favor germination was employed, but without success. 
After proper exposure to moisture, the place of the germ 
was usually found to be occupied by a slimy, putrefying 
liquid. 

The fact ai:)pears to be that the circumstances under 
which the seed is kept greatly influence the duration of 
its vitality. If seeds, when first gathered, be thoroughly 
dried, and then sealed up in tight vessels, or otherwise 
kept out of contact of the air, there is no reason why 
their' vitality should not endure for ages. Oxygen and 
moisture, not to mention insects, are the agencies that 
usually put a speedy limit to the duration of the germina- 
tive power of seeds. 

In agriculture it is a general rule that the newer the 
seed the better the results of its use. Experiments have 
proved that the older the seed the more numerous the 
failures to germinate, and the weaker the plants it pro- 
duces. 

Londet made trials in 1856-7 with seed-wheat of the 
years 1856, '55, '54, and '53. 

The following table exhibits the results, which illustrate 
the statement just made. 

Per cent of seeds Length of leaves four days ^3r/T«?C S?^ 
spi^outed. after coming up. hundred seeds. 

Seed of 1853, none 

" " 1854, 51 0.4 to 0.8 inches 269 

" " 1855, 73 1.2 " 365 

" " 1856, 74 1.6 " 404 

The results of similar experiments made by Haberlandt 
on various grains, are contained in the following table : 

Per cent of seeds that germinated in 1861 from the years : 



I 



I 





1850 '51 


'54 


'55 


'57 


'58 


'59 


'60 


Wheat, 





8 


4 


73 


60 


84 


96 


Hye, 


' 














48 


100 


Barley, 





24 





48 


33 


92 


89 


Oats, 


60 


56 


48 


72 


32 


80 


96 


Maize, 


not tried. 


76 


56 


not tried. 


77 


100 


97 



BEPJRODUCTIVE OEGAITS OF PLANTS. 307 

Results of the Use of long-kept Seeds. — The fact that old 
seeds yield weak plants is taken advantage of by the florist 
in producing new varieties. It is said that while the one- 
year-old seeds of Ten-weeks Stocks yield single flowers, 
those which have been kept four years give mostly double 
flowers. ' 

In case of melons, the experience of gardeners goes to > 
show that seeds which have been kept several, even seven 
years, though less certain to come up, yield plants that 
give the greatest returns of fruit ; while plantings of new 
seeds run excessively to vines. 

Unripe Seeds. — Experiments by Lucanus prove that 
seeds gathered while still unripe, — when the kernel is soft 
and milky, or, in case of cereals, even before starch has 
formed, and when the juice of the kernel is like water in 
appearance, — are nevertheless capable of germination, espe- 
cially if they be allowed to dry in connection with the stem 
(after-ripening.) Such immature seeds, however, have less 
vigorous germinative power than those which are allowed 
to mature perfectly ; when sown, many of them fail to 
come up, and those which do, yield comparatively weak 
plants at first and in poor soil give a pooj-er harvest than 
well-ripened seed. In rich soil, however, the plants which 
do appear from unripe seed, may, in time, become as vig- 
orous as any. (Lucanus, Vs. St., lY, p. 253.) 

According to Siegert, the sowing of unripe peas tends to 
produce earlier varieties. Liebig says : " The gardener is 
aware that the flat and shining seeds in the pod of the 
Stock Gillyflower will give tall plants with single flowers, 
while the shriveled seeds will furnish low plants with 
double flowers throughout." 

Dwarfed or Light Seeds.— Dr. Muller, as well as Hell- 
riegel, found that light grain sprouts quicker but yields 
weaker plants, and is not so sure of germinating as heavy 
grain. 



308 HOW CEOPS GROW. 

Baron Liebig asserts {Natural Laws of Esasbandry^ 
Am. Ed.^ 1863, p. 24) that "the strength and number of 
the roots and leaves formed in the process of germination, 
are, (as regards the non-nitrogenous constituents,) in di- 
rect proportion to the amount of starch in the seed^ 
Further, "poor and sickly seeds will produce stunted 
plants, which will again yield seeds bearing in a great 
measure the same character." On the contrary, he states 
(on page 61 of the same book, foot note,) that " Boussing- 
ault has observed that even seeds weighing two or three 
milligrames, (l-30th or l-20th of a grain,) sown in an ab- 
solutely sterile soil, will produce plants in which all the 
organs are developed, but their weight, after months, does 
not amount to much more than that of the original seed. 
The plants are reduced in all dimensions ; they may, how- 
ever, grow, flower, and even bear seed, which only requires 
a fertile soil to produce again a plant of the natural size.'''' 
These seeds must be diminutive, yet placed in a fertile soil 
they give a plant of normal dimensions. We must thence 
conclude that the amount of starch, gluten, etc. — in other 
words the Aveight of a seed — is not altogether an index of 
the vigor of the plant that may spring from it. 

Schubert, whose observations on the roots of agricul- 
tural plants are detailed in a former chapter (p. 242,) says, 
as the result of much investigation — " the vigorous devel- 
opment of plants depends far less upon the size and 
weight of the seed than upon the depth to which it is cov- 
ered with earth, and upon the stores of nourishment which 
it finds in its first period of life." 

Value of seed as related to its Density. — From a series 
of experiments made at the Royal Ag. College at Ciren- 
cester, in 1863-4, Prof. Church concludes that the value 
of seed-wheat stands in a certain connection with its spe- 
cific gravity^ {Practice with Science, p. 107, London, 1865.) 
He found : — 



EEPKODUCTIVE ORGANS OF PLANTS. 309 

1. That seed- wheat of the greatest density produces 
the densest seed. 

2. The seed- wheat of the greatest density yields the 
greatest amount of dressed corn. 

3. The seed- wheat of medium, density generally gives 
the largest number of ears, but the ears are poorer than 
those of the densest seed. 

4. The seed-wheat of medium density generally pro- 
duces the largest number of fruiting plants. 

5. The seed-wheats which sink in water but float in a 
liquid having the specific gravity 1.247, are of very low 
value, yielding, on an average, but 34.4 lbs. of dressed 
grain for every 100 yielded by the densest seed. 

The densest grains are not, according to Church, always 
the largest. The seeds he experimented with ranged from 
sp. gr. 1.354 to 1.401. 



DIVISION III. 

LIFE OF THE PLANT, 

CHAPTER L 
GERMINATIOiq". 



§. 1. 
INTEODUCTORT. 

Having traced the composition of vegetation from its 
ultimate elements to the proximate organic compounds, 
and studied its structure in the simple cell as well as in the 
most highly developed plant, and, as far as needful, explain- 
ed the characters and functions of its various organs, we 
approach fhe subject of Vegetable Life and IN'utrition", 
and are ready to inquire how the plant increases in bulk and 
weight and produces starch, sugar, oil, albuminoids, etc., 
v»^hich constitute directly or indirectly almost the entire 
food of animals. 

The beginning of the individual plant is in the seed, at 
the moment of fertilization by the action of a pollen tube 
on the contents of the embryo-sack. Each embryo whose 
development is thus ensured, is a plant in miniature, or 
rather an organism that is capable, under proper circum- 
stances, of unfolding into a plant. 
310 



GERMINATION. 311 

The first process of development, wherein the young 
plant commences to manifest its separate life, and in which 
it is shaped into its proper and peculiar form, is called 
germination. 

The General Process and Conditions of Germination 
are familiar to all. In agriculture and ordinary garden- 
ing we bury the ripe and sound seed a little way in the 
soil, and in a few days, it usually sprouts, provided it finds 
a certain degree of warmth and moisture. 

Let us attend somewhat in detail first to the phenomena 
of germination and afterward to the requirements of the 
awakening seed. 

§2. 
THE PHENOMENA OF GERMINATION. 

The student will do well to watch with care the various 
stages of the act of germination, as exhibited in several 
species of plants. For this purpose a dozen or more seeds 
of each plant are sown, the smaller, one-half, the larger, one 
inch deep, in a box of earth or saw-dust, kept duly warm 
and moist, and one or two of each kind are uncovered and 
dissected at successive intervals of 12 hours until the 
l)rocess is complete. In this way it is easy to trace all the 
visible changes which occur as the embryo is quickened. 
The seeds of the kidney-bean, pea, of maize, buckwheat, 
and barley, may be employed. 

We thus observe that the seed first absorbs a large 
amount of moisture, in consequence of which it swells and 
becomes more soft. We see the germ enlarging beneath 
the seed coats, shortly the integuments burst and the radi- 
cle, appears, afterward the plumule becomes manifest. 

In all agricultural plants the radicle buries itself in the 
soil. The plumule ascends into the atmosphere and seeks 
exposure to the direct light of the sun. 



312 HOW CROPS GKOW. 

The endosperm, if the seed have one, and in many cases 
the cotyledons (so with the horse-bean, pea, maize, and 
barley), remain in the place where the seed was deposited. 
In other cases (kidney-bean, buckwheat, squash, radish, 
etc.,) the cotyledons ascend and become the first pair of 
leaves. 

The ascending plumule shortly unfolds new leaves, and 
if coming from the seed of a branched plant, lateral buds 
make their appearance. The radicle divides and subdi- 
vides in beginning the issue of true roots. 

When the plantlet ceases to derive nourishment from 
the mother seed, the process is finished. 



§3. 

THE CONDITIONS OF GERMINATION. 

As to the Conditions of Germination we have to con- 
sider in detail the following :— 

a I Temperature I — A certain range of warmth is essen- 
tial to the sprouting of a seed. — Goppert, who experiment- 
ed wdth numerous seeds, observed none to germinate be- 
low 39«'. 

Sachs has ascertained for various agricultural seeds the 
extreme limits of warmth at which germination is possi- 
ble. The lowest temperatures range from 41° to 55°, the 
highest, from 102° to 116°. Below the minimum temper- 
ature a seed preserves its vitality, above the maximum it 
is killed. He finds, likewise, that the point at which the 
most rapid germination occurs is intermediate between 
these two extremes, and lies between 79° and 93°. Either 
elevation or reduction of temperature from these degrees 
retards the act of sproutihg. 

In the following table are given the special tempera- 
tures for six common plants. 





GEEMINATIOIT. 


31 




Loioest 


Highest 


Temperature of most 




Temperature. 


Temperature. 


rapid Germination. 


Wheat, 


4rF. 


104° F. 


84° F. 


Barley, 


41. 


104. 


84. 


Pea, 


44.5 


103. 


84. 


Maize, 


48. 


115. 


93. 


Scarlet-bean, 


49. 


111. 


79. 


Sqiiasli, 


54. 


115. 


93. 



For all agricultural plants cultivated in New England, 
a range of temperature of from 55° to 90° is adapted for 
healthy and speedy germination. 

It will be noticed in the above Table that the seeds of 
plants introduced into northern latitudes from tropical re- 
gions, as the squash, bean, and maize, require and endure 
higher temperatures than those native to temperate lati- 
tudes, like wheat and barley. The extremes given 
above are by no means so wide as would be found were 
we to experiment with other plants. It is probable that 
some seeds will germinate nearly at 32°, or the freezing 
jDoint of water, while the cocoa-nut is said to yield seed- 
lings with greatest certainty when the heat of the soil is 
120°. 

Sachs has observed that the temperature at w^hich 
germination takes place materially influences the relative 
development of the parts, and thus the form of the seed- 
ling. According to this industrious experimenter, very 
low temperatures retard the production of new rootlets, 
buds, and leaves. The rootlets which are rudimentary in 
the embryo become, however, very long. On the other 
hand, very high temperatures cause the rapid formation 
of new roots and leaves, even before those existing in the 
germ are fully unfolded. The medium and most favora- 
ble temperatures bring the parts of the embryo first into 
development, at the same time the rudiments of new or- 
gans are formed which are afterward to unfold. 

h. Moisture* — A certain amount of moisture is indis- 
pensable to all growth. In germination it is needful that 
14 



314 HOW CEOPS GKOW. 

the seed should absorb water so that motion of the con- 
tents of the germ-cells can take place. Until the seed is 
more or less imbued with moisture, no signs of sprouting 
are manifested, and if a half-sprouted seed be allowed to 
dry the process of growth is effectually checked. 

The degree of moisture different seeds will endure or 
require is exceedingly various. The seeds of aquatic 
plants naturally germinate when immersed in water. The 
seeds of many land-plants, indeed, will quicken under wa- 
ter, but they germinate most healthfully when moist but 
not wet. Excess of water often causes the seed to rot. 

c. Oxygen Gas. — Free Oxygen^ as contained in the air, 
is likewise essential. Saussure demonstrated by experi- 
ment that proper germination is impossible in its absence, 
and cannot proceed in an atmosphere of other gases. As 
we shall presently see, the chemical activity of oxygen 
appears to be the means of exciting the growth of the 
embryo. 

d. Light. — It has been taught that light is prejudicial 
to germination, and that therefore seed must be covered. 
(Johnston^ s Lectures on Ag. Chem. c& Geology, 2d Eng, 
Ed., pp. 226 & 227). When, however, we consider that 
nature does not bury seeds but scatters them on the sur- 
face of the ground of forest and prairie, where they are, at 
the most, half-covered and by no -means removed from the 
light, we cannot accept such a doctrine. The warm and 
moist forests of tropical regions, which, though shaded, 
are by no means dark, are covered with sprouting seeds. 
The gardener knows that the geeds of heaths, calceolarias, 
and some other ornamental plants, germinate best when 
uncovered, and the seeds of common agricultural plants 
will sprout when placed on moist sand or saw-dust, with 
apparently no less readi^jess than when buried oi^t of sight. 

Finally, K. Hoffmann {Jahreshericht uher Agricyiltuf 
Chem., 1864, p. 110) has found in experiments witl^ ;2^ 



GERMI1S-ATI0N-. 315 

kinds of agricultural seeds that light exercises no appreci- 
able influence of any kind on germination. 

The Time required for Germiniition varies exceedingly 
according to the kind of seed. As ordinarily observed, 
the fresh seeds of the willow begin to sprout within 12 
hours after falling to the ground. Those of clover, wheat, 
and other grains, germinate in three to five days. The 
fruits of the walnut, pine, and larch, lie four to six weeks 
before sprouting, while those of some species of ash, beech, 
and maple, are said not to germinate before the expiration 
of 1^ or 2 years. 

The starchy and thin-skinned seeds quicken most readi- 
ly. The oily seeds are in general more slow, while such 
as are situated within thick and horny envelopes require 
the longest periods to excite growth. 

The time necessary for germination depends naturally 
upon the favorableness of other conditions. Cold and 
drought delay the process, when they do not check it al- 
together. Seeds that are buried deeply in the soil may re- 
main for years, preserving, but not manifesting, their vital- 
ity, because they are either too dry, too cold, or have not 
sufiicient access to oxygen to set the germ in motion. 

To speak with precision, we should distinguish the time 
from planting the dry seed to the commencement of germ- 
ination which is marked by the rootlet becoming visible, 
and the period that elapses until the process is complete, 
i. e., until the stores of the mother-seed are exhausted, 
and the young plant is wholly cast upon its own resources. 

At 41° F. in the experiments of Haberlandt, the rootlet 
issued after 4 days, in the case of rye, and in 5-7 days in 
that of the other grains and clover. The sugar-beet, how- 
ever, lay at this temperature 22 days before beginning to 
sprout. 

At 51°, the time was shortened about one-half in case 
of the seeds just mentioned. Maize required 11, kidney- 
beans 8, and tobacco 31 days at this temperature. 



316 HOW CEOPS GROW. 

At 65° the grains, clover, peas, and flax, began to sprout 
in one to two days ; maize, beans, and sugar-beet, in 3 
days, and tobacco in 6 days. 

The time of completion varies with the temperature 
much more than that of beginning. It is, for example, ac- 
cording to Sachs, 

at 41- 55° for wheat and barley 40-45 days, 
" 95-100° " " " " 10-13 *' 

At a given temperature small seeds complete germina- 
tion much sooner than large ones. Thus at 55-60° the 
process is finished with beans in 30-40 days. 

With maize in 30-35 days. 
" wheat "20-25 " 
" clover " 8-10 " 

These differences are simply due to the fact that the 
smaller seeds have smaller stores of nutriment for the 
young plant, and are therefore more quickly exhausted. 

Proper Depth of Sowing. — The soil is usually the me- 
dium of moisture, warmth, etc., to the seed, and it affects 
germination only as it influences the supply of these 
agencies ; it is not otherwise essential to the process. The 
burying of seeds, when sown in the field or garden, serves 
to cover them away from birds and keep them from drying 
up. In the forest, at spring-time, we may see innumerable 
seeds sprouting upon the surface, or but half covered with 
decayed leaves. 

While it is the nearly universal result of experience in 
temperate regions that agricultural seeds germinate most 
surely when sown at a depth not exceeding 1-3 inches, 
there are circumstances under which a widely different 
practice is admissible or even essential. In the light and 
porous soil of the gardens of ISTew Haven, peas may be 
sown 6 to 8 inches deep without detriment, and are 
thereby better secured from the ravages of the domestic 
pigeon. 

The Moqui Indians, dwelling upon the table lands 



GERMINATI01S-. 317 

of the higher Colorado, deposit the seeds of maize 12 or 
14 inches below the surface. Thus sown, the plant 
thrives, while, if treated according to the plan usual in the 
United States and Europe, it might never appear above 
ground. The reasons for such a procedure are the follow- 
ing : The country is without rain and almost without dew. 
In summer the sandy soil is continuously parched by the 
sun at a temperature often exceeding 100° in the shade. 
It is only at the depth of a foot or more that the seed finds 
the moisture needful for its growth, — ^moisture furnished 
by the melting of the winter snows.* 

R. Hoffmann, experimenting in a light, loamy sand, upon 
24 kinds of agricultural and market-garden seeds, found 
that all perished when buried 12 inches. When planted 
10 inches deep, peas, vetches, beans, and maize, alone came 
up ; at 8 inches there appeared, besides the above, wheat, 
miUet, oats, barley, and colza ; at 6 inches those already 
mentioned, together with winter colza, buckwheat, and 
sugar-beets ; at 4 inches of depth the above, and mustard, 
red and white clover, flax, horseradish, hemp, and turnips ; 
finally, at 3 inches, lucern also appeared. Hoffmann 
states that the deep-planted seeds generally sprouted most 
quickly, and all early differences in development disap- 
peared before the plants blossomed. 

On the other hand, Grouven, in trials with sugar-beet 
seed, made, most probably, in a well-manured and rather 
heavy soil, found that sowing at a depth of |- to 1^ inches, 
gave the earliest and strongest plants ; seeds deposited at 
a depth of 2|- inches required 5 days longer to come up 
than those planted at f in. It was further shown that 
seeds sown shallow in a fine wet clay required 4-5 days 
longer to come up than those placed at the same depth 
in the ordinary soil. 

Not only the character of the soil, which influences the 



* For these intercstincj facts the writer is indebted to Prof. J. S. Newberry. 



318 HOW CROPS GROW. 

supply of air, and warmth; but the kind of weather, 
which determines both temperature and degree of moist- 
ure, have their effect upon the time of germination, and 
since these conditions are so variable, the rules of practice 
are laid down, and must be received with, a certain latitude. 



§4. 



THE CHEMICAL PHYSIOLOGY OF GERMINATION. 

The N'uTEiTioiN- of the Seedling. — ^The young plant 
grows at first exclusively at the expense of the seed. It 
may be aptly compared to the suckling animal, which, 
when new-born, is incapable of providing its own nourish- 
ment, but depends upon the milk of its mother. 

The JSTutrition of the Seedling falls into three processes, 
which, though distinct in character, proceed simultaneous- 
ly. These are, 1, Solution of the Nutritive Matters of 
the Cotyledons or Endosperm ' 2, Transfer ; and 3, As- 
similation of the same. 

1. The Act of Solution has no difficulty in case of dex- 
trin, gum, the sugars, albumin, and casein. The water 
which the seed imbibes to the extent of one-fourth to 
five-fourths of its weight, at once dissolves them. 

It is otherwise with the fats or oils, with starch and 
with gluten, which, as such, are nearly or altogether insol- 
uble in water. In the act of germination provision is 
made for transforming these bodies into the soluble ones 
above mentioned. So far as these changes have been 
traced, they are as follows : 

Solution of Fats. — Sachs has recently found that squash- 
seeds, which, when ripe, contain no starch, sugar, or dex- 
trin, but are very rich in oil (50° l^,,) and albuminoids 



GERMINATIOJS-. 319 

(40° lo) suffer by germination such chemical change tliat the 
oil rapidly diminishes in quantity (nine-tenths disappears^ 
while at the same time starch, and, in some cases, sugar, is 
formed. ( Vs. St., Ill, p. 1.) 

Solution of Starch. — The starch that is thus organized 
from the fat of the oily seeds, or that which exists ready- 
formed in the farinaceous (floury) seeds, undergoes further 
changes, which have been previously alluded to (p. 78), 
whereby it is converted into substances that are soluble 
in water, viz., dextrin and grape or cane sugar. 

Solution of Albuminoids. — ^Finally, the insoluble al- 
buminoids are gradually transformed into soluble modifi- 
cations. 

Chemistry of Malt» — The preparation and properties 
of malt may serve to give an insight into the nature of 
the chemical metamorphoses that have just been indicated. 

The preparation is in this wise. Barley or wheat 
(sometimes rye) is soaked in water until the kernels are 
soft to the fingers ; then it is drained and thrown up in 
heaps. The masses of soaked grain shortly dry, become 
heated, and in a few days the embryos send forth their 
radicles. The heaps are shoveled over, and spread out so 
as to avoid too great a rise of temperature, and when the 
sprouts are about half an inch in length, the germination 
is checked by drying. The dry mass, after removing the 
sprouts (radicles,) is malt, such as is used in the manufac- 
ture of beer. 

Malt thus consists of starchy seeds whose germination 
has been checked while in its early stages. The only prod- 
uct of the beginning growth — the sprouts — being remov- 
ed, it exhibits in the residual seed the first results of the 
process of solution. 

The following figures, derived from the researches of 
Stein, in Dresden, ( Wilda^s GentralUatt, 1860, 2, pp. 8- 
23,) exhibit the composition of 100 parts of Barley, and 



320 HOW CROPS GEOW. 

of the 92 parts of Malt, and the 2| of Sprouts whicli 100 
parts of barley yield.* 

100 pts. of) inpis.of) i 2Ho/ 



Composition of 

Barley. 



•|_j92i?^s.o/) J 2H0/ I 
\{ Malt. \ [Sprouts.S 



Ash 2.42 2.11 0.29 

Starch 54.48 47.43 

Fat 3.56 2.09 0.08 

Insoluble Albuminoids 11.03 9.02 0.37 

Soluble " ; 1.26 1.96 0.40 

Dextrin 6.50 6.95 | 

Extractive Matters (soluble in wa- >• 0.47 

ter and destitute of nitrogen). . 0.90 3.68 ) 

Cellulose 19.86 18.76 0.89 



100 92 2.5 

It is seen from the above statement that starch, fat, and 
insoluble albuminoids, have diminished in the malting 
process; while soluble albuminoids, dextrin, and other 
soluble non-nitrogenous matters, have somewhat increased 
in quantity. With exception of 3° !„ of soluble " extractive 
matters," \ the diversities in composition between barley 
and malt are not striking. 

The properties of the two are, however, remarkably dif- 
ferent. If malt be pulverized and stirred in warm water 
(155° F.) for an hour or two, the whole of the starch dis- 
appears, while sugar and dextrin take its place. The 
former is recognized by the sweet taste of the wort, as the 
solution is called. On heating the wort to boiling, a 
quantity of albumin is coagulated, and may be separated 
by filtering. This comes in part from the transformation 
of the insoluble albuminoids of the barley. On adding 



* The analyses refer to the materials in the dry state. Ordinarily they con- 
tain from 10 to Voper cent of water. It must not he omitted to mention that the 
proportions of malt and sprouts, as well as their composition, vary somewhat 
according to circumstances ; and furthermore, the best analyses which it is pos- 
sible to make are but approximate. 

t The term extractive matters is here applied to soluble substances, whose 
precise nature is not understood. They constitute a mixture which the chemist 
is not able to analyze. 



GERMINATION". 321 

to the filtered liquid its own bulk of alcohol, dextrin be- 
comes evident, being precipitated as a white powder. 

Furthermore, if we mix 2 — 3 parts of starch with one 
of malt, we find that the whole undergoes the same change. 
An additional quantity of starch remains unaltered. 

The process of germination thus developes in- the seed 
an agency by which the conversion of starch into soluble 
carbohydrates is accomplished with great rapidity. 

Diastase* — ^Payen & Persoz attribute this action to a 
nitrogenous substance which they term Diastase^ and 
which is found in the germinating seed in the vicinity of 
the embryo, but not in the radicles. They assert that one 
part of diastase is capable of transforming 2,000 parts of 
starch, first into dextrin and finally into sugar, and that 
malt yields ^loth of its weight of this substance. 

A short time previous to the investigations of Pay en & 
Persoz (1833,) Saussure found that Mucidin^ the soluble 
nitrogenous body which may be extracted from gluten 
(p. 101,) transforms starch in the manner above described, 
and it is now known that any albuminoid may produce 
the same eifect, although the rapidity of the action and 
the amount of efiect are usually far less than that exhibit- 
ed by the so-called diastase. 

In order, however, that the albuminoids may transform 
starch as above desciibed, it is doubtless necessary that 
they themselves enter into a state of alteration ; they are 
in part decomposed and disappear in the process. 

These bodies thus altered become /6rme?zi^5. 

It must not be forgotten, however, that in all cases in 
which the conversion of starch into dextrin and sugar is 
accomplished artificially, an elevated temperature is re- 
quired, whereas in the natural process, as shown in the 



* Saussure designated this Tjody mudn, but this term being established as the 
name of the characteristic ingredient of animal mucus, Kitthausen has replaced 
it by mucidin. 

14* 



322 



HOW CROPS GROW. 



germinating seed, the change goes on at ordinary or even 
low temperatures. 

It is generally taught that oxygen acting on the album- 
inoids in i^resence of water and within a certain range of 
temperature induces the decomposition which confers on 
them the power in question. 

The necessity for oxygen in the act of germination has 
been thus accounted for, as needful to the solution of 
the starch, etc., of the cotyledons. 

This may be true at first, but, as we shall presently see, 
the chief action of oxygen is probably of another kind. 

How diastase or other similar substances accomplish the 
change in question is not certainly known. 

Soluble Starch* — The conversion of starch into sugar 
and dextrin is thus in a sense explained. This is not, how- 
ever, the only change of 
which starch is susceptible. 
In the bean, {Phaseolus 
muWflorus)^ Sachs {Sitz- 
ungsherichte der Wiener 
AJcad., XXXYII, 57) in- 
forms us that the starch of 
the cotyledons is dissolved, 
passes into the seedling, and 
reappears (in part, at least) 
as starch, without conver- 
sion into dextrin or sugar, 
as these substances do not 
appear in the cotyledons during any period of germina- 
tion, except in small quantity near the joining of the 
seedling. Compare p. 64, Unorganized Starch. 

The same authority gives the following account of 
the microscopic changes observed in the starch-grains 
themselves, as they undergo solution. The starch-grains 
of the bean have a narrow interior cavity, (as seen in 
fig. 65, 1.) This at first becomes filled with a liquid. 




GERMINATION?-. 823 

Next, the cavity appears enlarged (2,) its borders assume 
a corroded appearance (3, 4,) and frequently channels are 
seen extending to the surface (4, 5, 6.) Finally, the 
cavity becomes so large, and the channels so extended, 
that the starch-grain falls to pieces (7, 8.) Solution con- 
tinues on the fragments until they have completely disap- 
peared. In this process it is most probable that the starch 
assumes the liquid form without loss of its proper chemi- 
cal characters, though it ceases to strike a blue color with 
iodine.* 

Soluble Albuminoids.— As we have seen (p. 104,) in- 
soluble animal fibrin and casein, by long keeping with 
imperfect access of air, pass into soluble bodies, and lat- 
terly E. Mulder has shown that diastase rapidly accom- 
plishes the same change. It would appear, in fact, that 
the conversion of a small quantity of any albuminoid into 
a ferment, by oxidation, is sufficient to render the whole 
soluble. The ferment exerts on the bodies from which it 
is formed, an action similar to that manifested by it to- 
wards starch and other carbohydrates. 

The production of small quantities of acetic and lactic 
acids (the acids of vinegar and of sour milk) has been 
observed in germination. These acids perhaps assist in 
the solution of the albuminoids. 

Gaseous Products of Germination. — Before leaving 
this part of our subject, it is proper to notice some other 
results of germination which have been thought to belong 
to the process of solution. On referring to the table of 
the composition of malt, we find that 100 parts of dry 
barley yield 92 parts of malt and 2|- of sprouts, leaving 
5|- parts unaccounted for. In the malting process 1|- parts 
of the grain are dissolved in the water in which it is 
soaked. The remaining 4 parts escape into the atmos- 
phere in the gaseous form. 

* According to Licbig, this blue reaction depends upon the adhesion of the 
iodine to the starch, and is not the result of ^ chenjical combination. 



324 HOW CEOPS GKOW. 

Of the elements that assume the gaseous condition, car- 
bon does so to the greatest extent. It unites with atmos- 
pheric oxygen (partly with the oxygen of the seed, ac- 
cording to Oudemans) producing carbonic acid gas (CO^.) 
Hydrogen is likewise separated, partly in union with 
oxygen, as water (H„0), but to some degree in the free 
state. Free nitrogen appears in considerable amount, 
(Schulz, Jour, far PraJct. Chem.^ 87, p. 163,) while very 
minute quantities of Hydrogen and of Nitrogen combine 
to gaseous ammonia (NHg.) 

Heat developed in Germination. — These chemical 
changes, like all processes of oxidation, are accompanied 
with the production of heat. The elevation of tempera- 
ture may be imperceptible in the germination of a single 
seed, but it nevertheless occurs, and is doubtless of much 
importance in favoring the life of the young plant. The 
heaps of sprouting grain seen in the malt-house warm so 
rapidly and to such an extent, that much care is requisite 
to regulate the process ; otherw^ise the malt is damaged by 
over-heatinsr. 

2. The Transfer of the Nntriment of the Seedling 

from the cotyledons or endosperm where it has undergone 
solution, takes place through the medium of the water 
which the seed absorbs so largely at first. This water 
fills the cells of the seed, and, dissolving their contents, 
carries them into the young plant as rapidly as they are 
required. The path of their transfer lies through the 
point where the embryo is attached to the cotyledons ; 
thence they are distributed at first chiefly downwards into 
the extending radicles, after a little while both down- 
wards and upwards toward the extremities of the seedling. 
Sachs has observed that the carbohydrates (sugar and 
dextrin) occupy the cellular tissue of the rind and pith, 
which are penetrated by numerous air-passages ; while at 
first the albuminoids chiefly difluse themselves through 



GERMINATIOIT. 325 

the interaiediate cambial tissue, which is destitute of air- 
passages, and are present in largest relative quantity at 
the extreme ends of the rootlets and of the plumule. 

In another chapter we shall notice at length the phenom- 
ena and physical laws which govern the diffusion of liq- 
uids into each other and through membranes similar to 
those which constitute the walls of the cells of plants, 
and there shall be able to gather some idea of the causes 
which set up and maintain the transfer of the materials 
of the seed into the infant plant. 

3. Assimilation is the conversion of the transferred nutri- 
ment into the substance of the plant itself. This process 
involves two stages, the first being a chemical, the second, 
a structural transformation. 

The chemical changes in the embryo are, in part, simply 
the reverse of those which occur in the cotyledons ; viz., 
the soluble and structureless proximate principles are met- 
amorphosed into the insoluble and organized ones of the 
same chemical comj)osition. Thus, dextrin may pass into 
cellulose, and the soluble albuminoids may revert in part 
to the insoluble condition in which they existed in the 
ripe seed. 

But many other and more intricate changes proceed in 
in the act of assimilation. With reojard to a few of these 
we have some imperfect knowledge. 

Dr. Sachs informs us that when the embryo begins to 
grow, its expansion at first consists in the enlargement of 
the ready-formed cells. As a part elongates, the starch 
which it contains (or which is formed in the early stages 
of this extension), disappears, and sugar is found in its stead, 
dissolved in the juices of the cells. When the organ has 
attained its full size, sugar can no longer be detected ; 
while the walls of the cells are found to have grown both 
in circumference and thickness, thus indicating the accumu- 
lation of cellulose. 



326 HOW CROPS GROW. 

Oxygen Gas needful to Assimilation. — Traube has made 
some experiments, which seem to prove conclusively that 
the process of assimilation requires free oxygen to surround 
and to be absorbed by the growing parts of the germ. 
This observer found that newly-sprouted pea-seedlings 
continued to develope in a normal manner when the cot- 
yledons, radicles, and lower part of the stem, were with- 
drawn from the influence of oxygen by coating with var- 
nish or oil. On the other hand, when the tip of the 
plumule, for the length of about an inch, was coated with 
oil thickened with chalk, or when by any means this part 
of the plant was withdrawn from contact with free oxygen, 
the seedling ceased to grow, withered, and shortly perish- 
ed. Traube observed the elongation of the stem by the 
following expedient. 

A young pea-plant was fastened by the cotyledons to a 
rod, and the stem and rod were both graduated by deli- 
cate cross-lines, laid on at equal intervals, by means of a 
brush dipped in a mixture of oil and indigo. The growth 
of the stem was now manifest by the widening of the 
spaces between the lines; and by comparison with those 
on the rod, Traube remarked that no growth took place 
at a distance of more than 10-12 lines from the base of 
the terminal bud. 

Here, then, is a coincidence which appears to demonstrate 
that free oxygen must have access to a growing part. 
The fact is further shown by varnishing one side of the 
stem of a young pea. The varnished side ceases to extend, 
the uncoated portion continues enlarging, which results in, 
and is shown by, a curvature of the stem. 

Traube further indicates in what manner the elabora- 
tion of cellulose from sugar may require the cooperation 
of oxygen and evolution of carbonic acid, as expressed by 
the subjoined equation. 

Cfliicose. OxT/gen-. Carbonic Acid. Water. CdMose. 

3 (Ci2 H.24 Oio) + 340 = 13 (CO2) + 14 (H2O) + Cio Uoo Oio- 



FOOD AFTER GERMINATION-. 327 

When tlie act of germination is finished, Avhich occurs 
as soon as the cotyledons and endosperm are exhausted 
of all their soluble matters, the plant begins a fully inde- 
pendent life. Previously, however, to being thus thrown 
upon its own resources, it has developed all the organs 
needful to collect its food from without ; it has unfolded 
its perfect leaves into the atmosphere, and pervaded a por- 
tion of soil with its rootlets. 

During the latter stages of germination it gathers its 
nutriment both from the parent seed and from the exter- 
nal sources which afterward serve exclusively for its sup- 
port. 

Being fully provided with the apparatus of nutrition, 
its development suffers no check from the exhaustion of 
the mother seed, unless it has germinated in a sterile soil, 
or under other conditions adverse to vegetative life. 



CHAPTER IL 



THE FOOD OF THE PLANT WHEN INDEPENDENT OF THE 

SEED. 

This subject will be sketched in this place in but the 
briefest outlines. To present it fully would necessitate 
entering into a detailed consideration of the Atmosphere 
and of the Soil whose relations to the Plant, those of the 
soil especially, are very numerous and complicated. A 
separate volume is therefore required for the adequate 
treatment of these topics. 

The Roots of a plant, which are in intimate contact 
with the soil, absorb thence the water that fills the active 



328 HOW CROPS GEOW. 

cells ; they also imbibe such salts as the water of the soil 
holds in solution ; they likewise act directly on the soil, 
and dissolve substances, which are thus first made of avail 
to them. The compounds that the plant must derive from 
the soil are those which are found in its ash, since these 
are not volatile, and cannot, therefore, exist in the atmos- 
phere. The root, however, commonly takes up some other 
elements of its nutrition to which it has immediate access. 
Leaving out of view, for the present, those matters which, 
though found in the plant, appear to be unessential to its 
growth, viz., silica, soda and manganese, the roots absorb 
the following substances, viz. : 

Sulphates "j ( Potash. 

Phosphates [ .-. j Lime. 

Nitrates and f 1 Magnesia and 

Chlorides J [ Iron. 

These salts enter the plant by the absorbent surfaces of 
the younger rootlets, and pass upwards through the active 
portions of the stem, to the leaves and to the new-forming 
buds. 

The Leaves, which are unfolded to the air, gather from 
it Carbonic Acid Gas. This compound suffers decompo- 
sition in the plant ; its Carbon remains there, its Oxygen 
or an equivalent quantity, very nearly, is thrown off into 
the air again. 

The decomposition of carbonic acid takes place only by 
day and under the influence of the sun's light. 

From the carbon thus acquired and the elements of wa- 
ter with the cooperation of the ash-ingredients, the plant 
organizes the Carbohydrates. Probably glucose, perhaps 
dextrin or soluble starch, are the first products of this 
synthesis. 

The formation of carbohydrates appears to proceed in 
the chlorophyll-cells of the leaf 

The Albuminoids require for their production the pres- 
ence of a compound of JVitrogen. The salts of JVitrio 



POOD AFTER GEEMIN-ATIOI^-. 329 

Acid (nitrates) are commonly the chief, and may he the 
only supply of this element. 

The other proximate principles, viz. pectose, the fats, 
the alkaloids, and the acids, are built up from the same 
food-elements. In all cases the steps in the construc- 
tion of organic matters are unknown to us, or subjects of 
uncertain conjecture. 

The carbohydrates, albuminoids, etc., that are organized 
in the foliage, are not only transformed into the solid tis- 
sues of the leaf, but descend and diffuse to every active 
organ of the plant. 

The plant has within certain limits a power of selecting 
its food. The sea-weed, as has been remarked, contains 
more potash than soda, although the latter is 30 times 
more abundant than the former in the water of the ocean. 
Vegetation cannot, however, entirely shut out either ex- 
cess of nutritive matters or bodies that are of no use or 
even poisonous to it. 

The functions of the Atmosphere are essentially the, 
same towards plants, whether growing under the condi- 
tions of aquseculture, or under those of agriculture. 

The Soil, on the other hand, has offices which are peculiar 
to itself. We have seen that the roots of a plant have the 
power to decompose salts, e. g. nitrate of potash and 
chloride of ammonium (p. 170,) in order to appropriate 
one of their ingredients, the other being rejected. In 
aquseculture, the experimenter must have a care to re- 
move the substance which would thus accumulate to the 
detriment of the plant. In agriculture, the soil, by virtue 
of its chemical and physical qualities, renders such reject- 
ed matters comparatively insoluble, and therefore innoc- 
uous. 

The Atmosphere is nearly invariable in its composition 
at all times and over all parts of the earth's surface. Its 
power of directly feeding crops has, therefore, a natural 
limit, which cannot be increased by art. 



330 HOW CHOPS GEOW. 

The Soil, on the other hand, is very variable in compo- 
sition and quality, and may he enriched and improved, or 
deteriorated and exhausted. 

From the Atmosphere the crop can derive no appreci- 
able quantity of those elements that are found in its Ash. 

In the Soil, however, from the waste of both plants and 
animals, may accumulate large supplies of all the elements 
of the Volatile part of Plants. Carbon, certainly in the 
form of carbonic acid, probably or possibly in the condi- 
tion of Humus (Vegetable Mould, Muck), may thus be 
put, as food, at the disposition of the plant. Nitrogen is 
chiefly furnished to crops by the soil. Nitrates are formed 
in the latter from various sources, and ammonia-salts, to- 
gether with certain proximate animal principles, viz., 
urea, guanin, tyrosin, uric acid and hippuric acid, likewise 
serve to supply nitrogen to vegetation and are ingredients 
of the best manures. It is, too, from the soil that the 
crop gathers all the Water it requires, which not only 
serves as the fluid medium of its chemical and structural 
metamorphoses, but likewise must be regarded as the ma- 
terial from which it mostly appropriates the Hydrogen 
and Oxygen of its solid components. 



§2. 



THE JUICES OF THE PLANT, THEIR NATURE AND 
MOVEMENTS. 

Very erroneous notions are entertained with regard to 
the nature and motion of sap. It is commonly taught that 
there are two regular and opposite currents of sap circu- 
lating in the plant. It is stated that the " crude sap " is 
taken up from the soil by the roots, ascends through the 



MOTION OF THE JUICES. 331 

vessels (ducts) of the wood, to the leaves, there is concen- 
trated by evaporation, "elaborated" by the processes 
that go on in the foliage, and thence descends through the 
vessels of the inner bark, nourishing these tissues in its 
way down. The facts from which this theory of the sap 
first arose, all admit of a very different interpretation ; 
while numerous considerations demonstrate the essential 
falsity of the theory itself. 

Flow of sap in the plant — not constant or necessary. 
— ^We speak of the Flow of Sap as if a rapid current 
were incessantly streaming through the plant, as the blood 
circulates in the arteries and veins of an animal. This is 
an erroneous conception. 

A maple in early March, without foliage, with its whole 
stem enveloped in a nearly impervious bark, its buds 
wrapped up in horny scales, and its roots surrounded by 
cold or frozen soil, cannot be supposed to have its sap in 
motion. Its juices must be nearly or absolutely at rest, 
and when sap runs copiously from an orifice made in the 
trunk, it is simply because the tissues are charged with 
water under pressure, which escapes at any outlet that 
may be opened for it. The sap is at rest until motion is 
caused by a perforation of the bark and new wood. So, 
too, when a plant in early leaf is situated in an atmosphere 
charged with moisture, as happens on a rainy day, there is 
little motion of its sap, although, if wounded, motion will 
be established, and water will stream more or less from all 
parts of the plant towards the cut. 

Sap does move in the plant when evaporation of water 
goes on from the surface of the foliage. This always hap- 
pens whenever the air is not saturated with vapor. When - 
a wet cloth hung out, dries rapidly by giving up its 
moisture to the air, then the leaves of plants lose their 
water more or less readily, according to the nature of 
the foliage. 

Mr. Lawes found that in the moist climate of Eno^land 



332 HOW CROPS GEOW. 

common plants (Wheat, Barley, Beans, Peas, and Clover), 
exhaled dnring 5 months of growth, more than 200 times 
their (dry) weight of water. The water that thus evap- 
orates from the leaves is supplied by the soil, and en- 
tering the roots, rapidly streams upwards through the 
stem as long as a waste is to be supplied, but ceases when 
evaporation from the foliage is checked. 

The upward motion of sap is therefore to a great de- 
gree independent of the vital processes^ and comparatively 
inessential to the welfare of the plant. 

Flow of sap from the plant. "Bleeding." — ^It is a 

familiar fact, that from a maple tree " tapped " in spring- 
time, or from a grape-vine wounded at the same season, a 
copious flow of sap takes place, which continues for a num- 
ber of weeks. The escape of liquid from the vine is com- 
monly termed " bleeding," and while this rapid issue of 
sap is thus strikingly exhibited in comparatively few 
cases, bleeding aj^pears to be a universal phenomenon, one 
that may occur, at least, to some degree, under certain con- 
ditions with every plant. 

The conditions under which sap flows are various, ac- 
cording to the character of the i^lant. Our perennial 
trees have their annual period of active growth in the 
warm season, and their vegetative functions are nearly 
suppressed during cold weather. As spring approaches 
the tree renews its growth, and the first evidence of change 
Avithin is furnished by its bleeding when an opening is 
made through the bark into the young wood. A maple, 
tapped for making sugar, loses nothing until the spring 
warmth attains a certain intensity, and then sap begins to 
flow from the Avounds in its trunk. The flow is not con- 
stant, but fluctuates with the thermometer, being more 
copious when the weather is warm, and falling off" or suf- 
fering check altogether as it is colder. 

The stem of the living maple is always charged with 



MOTION OF THE JUICES. 333 

water, and never more so than in winter.* This water is 
either pumped into the plant, so to speak, by the root- 
power already noticed (p. 248,) or it is generated in the 
trunk itself. The water contained in the stem in cold 
weather is undoubtedly that raised from the soil in the 
autumn. That which first flows from an augur-hole, in 
March, may be simply what was thus stored in the trunk ; 
but, as the escape of sap goes on for 14 to 20 days at the 
rate of several gallons per day from a single tree, new 
quantities of water must be continually supplied. That 
these are pumped in from the root is, at first thought, dif- 
ficult to understand, because as we have seen (p. 250) the 
root-power is suspended by a certain low temperature 
(unknown in case of the maple) and the flow of sap often 
begins when the ground is covered with one or two feet 
of snow, and when we cannot suppose tlie soil to have a 
higher temperature than it had during the previous win- 
ter months. Nevertheless, it must be that the deeper 
roots are warm enough to be active all the winter through, 
and that they begin their action as soon as the trunk ac- 
quires a temperature sufficiently high to admit the move- 
ment of water in it. That water may be produced in the 
trunk itself to a slight extent is by no means impossible, 
for chemical changes go on there in spring-time with much 
rapidity, whereby the sugar of the sap is formed. These 
changes have not been sufficiently investigated, however, 
to prove or disprove the generation of water, and we 
must, in any case, assume that it is the root-power which 
chiefly maintains a pressure of liquid in the tree. 

The issue of sap from the maple tree in the sugar-season 



* Experiments made in Tharaud, Saxony, under direction of Stoeckhardt, 
show that the proportion of water, both in the bark and wood of trees, varies 
considerably in different seasons of the year, ranging, in case of the beech, from 
35 to 49 per cent of the fresh-felled tree. The greatest proportion of water in 
the wood was found in the months of December and January; in the bark, in 
March to May. The minimum of water in the wood occurred in May, June, and 
July ; in the bark, much irregularity was observed. Cliem. Ackersmann, 1866, 
p. 169. 



334 HOW CROPS GEOW. 

is closely connected with the changes of temperature that 
take place above ground. The sap begins to flow from a 
cut when the trunk itself is warmed to a certain point, 
and, in general, the flow appears to be the more rapid the 
warmer the trunk. During warm, clear days, the radiant 
heat of the sun is absorbed by the dark, rough surface of 
the tree most abundantly ; then the temperature of the 
latter rises most sjDcedily and acquires the greatest eleva- 
tion — even surpasses that of the atmosphere by several 
degrees ; then, too, the yield of sap is most copious. On 
clear nights, cooling of the tree takes place with corre- 
sponding rapidity ; then the snow or surface of the ground 
is frozen, and the flow of sap is checked altogether. 
From trees that have a sunny exposure, sap runs earlier 
and faster than from those having a cold northern aspect. 
Saj) starts sooner from the spiles on the south side of a 
tree than from those towards the north. 

Duchartre, ( Comptes Bendus, IX, 754,) passed a vine 
situated in a grapery, out of doors, and back again, 
through holes, so that a middle portion of the stem was 
exposed to a steady winter temperature ranging from 18 
to 10° F., while the remainder of the vine, in the house, 
was surrounded by an atmosphere of 70° F. Under 
these circumstances the buds within developed vigorously, 
but those without remained dormant and opened not a 
day sooner than buds upon an adjacent vine whose stem 
Avas all out of doors. That sap passed through the cold 
part of tlie stem was shown by the fact that the interior 
shoots sometimes wilted, but again recovered their turgor, 
which could only happen from the partial suppression and 
renewal of a supply of water through the stem. Payen 
examined the wood of the vine at the conclusion of the 
experiment, and found the starch w^hich it originally con- 
tained to have been equally removed from the warm and 
the exposed parts. 

That the rate at which sap passed through the stem was 



MOTION OP THE JUICES. 335 

influenced by its temperature is a plain deduction from 
the fact that the leaves within were found wilted in the 
morning, while they recovered toward noon, although the 
temperature of the air without remained below freezing. 
The wilting was no doubt chiefly due to the diminished 
power of the stem to transmit water ; the return of the 
leaves to their normal condition was probably the conse- 
quence of the warming of the stem by the sun's radiant 
heat.* 

One mode in which changes of temperature in the trunk 
influence the flow of sap is very obvious. The wood-cells 
contain, not only water, but air. Both are expanded by 
heat, and both contract by cold. Air, especially, under- 
goes a decided change of bulk in this way. Water ex- 
pands nearly one-twentieth in being warmed from 32° to 
212°, and air increases in volume more than one-third by 
the same change of temperature. When, therefore, the 
trunk of a tree is warmed by the sun's heat the air is ex- 
panded, exerts a pressure on the sap, and forces it out of 
any wound made through the bark and wood-cells. It 
only requires a rise of temperature to the extent of a few 
degrees to occasion from this cause alone a considerable 
flow of sap from a large tree. (Hartig.) 

If we admit that water continuously enters the deep-ly- 
ing roots whose temperature and absorbent power must 
remain, for the most part, invariable from day to day, we 
should have a constant slow escape of sap from the trunk 
were the temperature of the latter uniform and sufficiently 
high. This really happens at times during every sugar- 
season. When the trunk is cooled down to the freezing 
point, or near it, the contraction of air and water in the 
tree makes a vacuum there, sap ceases to flow, and air is 



* The temperature of the air is not always a sure indication of that of the 
solid bodies which it suiTounds. A thermometer will often rise by exposure of 
the hulb to the direct rays of the sun, 30 or 40° above its indications when in the 
shade. 



336 HOW CROPS GEOW. 

sucked in througli the spile ; as the trunk becomes heated 
again, the gaseous and liquid contents of the ducts ex- 
pand, the flow of sap is renewed, and proceeds with in- 
creased rapidity until the internal pressure passes its max- 
imum. 

As the season advances and the soil becomes heated, the 
root-power undoubtedly acts with increased vigor and 
larger quantities of water are forced into the trunk, but 
at a certain time the escape of sap from a wound suddenly 
ceases. At this period a new phenomenon supervenes. 
The buds which were formed the previous summer begin 
to expand as the vessels are distended with sap, and final- 
ly, when the temperature attains the proper range, they 
unfold into leaves. At this point we have a proper mo- 
tion of sap in the tree^ whereas before there was little mo- 
tion at all in the sound trunk, and in the tapped stem the 
motion was towards the orifice and thence out of the tree. 

The cessation of flow from a cut results from two cir- 
cumstances : first, the vigorous cambial growth, whereby 
incisions in the bark and wood rapidly heal up ; and sec- 
ond, the extensive evaporation that goes on from foliage. 

That evaporation of water from the leaves often pro- 
ceeds more rapidly than it can be supplied by the roots 
is shown by the facts that the delicate leaves of many 
plants wilt when the soil about their roots becomes dry, 
that water is often rapidly sucked into wounds on the 
stems of trees which are covered with foliage, and that 
the proportion of water in the wood of the trees of tem- 
perate latitudes is least in the months of May, June, and 
July. 

Evergreens do not bleed in the spring-time. The oak 
loses little or no sap, and among other trees great diversity 
is noticed as to the amount of water that escapes at a 
wound on the stem. In case of evergreens we have a 
stem destitute of all proper vascular tissue, and admitting 
a flow of liquid only through the perforations of the wood- 



COMPOSITION OF THE JUICES. 337 

cells, which, from their content of resinous matters, 
should imbibe water less readily than other kinds of wood. 
Again, the leaves admit of continual evaporation, and fur- 
nish an outlet to the water. The colored heart-wood ex- 
isting in many trees is impervious to water, as shown by 
the experiments of Boucherie and Hartig. Sap can only 
flow through the white, so-called sap-wood. In early June, 
the new shoots of the vine do not bleed when cut, nor 
does sap flow from the wounds made by breaking them 
off close to the older stem, although a gash in the latter 
bleeds profusely. In the young branches, there are no 
channels that permit the rapid efiiux of water. 

Composition of Sap. — The sap in all cases consists 
chiefly of water. This liquid, as it is absorbed, brings in 
from the soil a small proportion of certain saline matters 
— the phosphates, sulphates, nitrates, etc., of the alkalies 
and alkali-earths. It finds in the plant itself its organic 
ingredients. These may be derived from matters stored 
in reserve during a previous year, as in the spring sap of 
trees ; or may be newly formed, as in summer growth. 

The sugar of maple-sap, in spring, is undoubtedly pro- 
duced by the transformation of starch which is found 
abundantly in the wood in winter. According to Hartig, 
{Jour, far Prdkt. Gh.^ 5, p. 217, 1835,) all deciduous trees 
contain starch in their wood and yield a sweet spring sap, 
while evergreens contain little or no starch. Hartig re- 
ports having been able to procure from the root-wood of 
the horse-chestnut in one instance no less than 2Q per cent 
of starch. This is deposited in the tissues during sum- 
mer and autumn to be dissolved for the use of the plant 
in developing new foliage. In evergreens and annual, 
j)lants the organic matters of the sap are derived more di- 
rectly from the foliage itself. The leaves absorb carbonic 
acid and unite its carbon to the elements of water, with 
the production of sugar and other carbohydrates. In the 
leaves, also, probably nitrogen from the nitrates and am- 
15 



338 HOW CKOPS GEOW. 

monia-salts gathered by the roots, is united to carbon, hy- 
drogen, and oxygen, in the formation of albuminoids. 

Besides sugar, malic acid and minute quantities of al- 
bumin exist in maple sap. Towards the close of the 
sugar-season the sap appears to contain other organic sub- 
stances which render the sugar impure, brown in color, 
and of different flavor. 

It is a matter of observation that maple-sugar is whiter, 
purer, and " grains " or crystallizes more readily in those 
years when spring-rains or thaws are least frequent. This 
fact would appear to indicate that the brown organic 
matters which water extracts from leaf-mould may enter 
the roots of the trees, as is the belief of practical men. 

The spring-sap of many other deciduous trees of tem- 
perate climates contains sugar, but while it is cane sugar 
in the maple, in other trees it consists mostly or entirely 
of grape sugar. 

Sugar is the chief organic ingredient in the juice of the 
sugar cane, Indian corn, beet, carrot, turnip, and. parsnip. 

The sap that flows from the vine and from many culti- 
vated herbaceous plants contains little or no sugar ; in 
that of the vine, gum or dextrin is found in its stead. 

What has already been stated makes evident that we 
cannot infer the quantity of sap in a plant from what may 
run out of an incision, for the sap that thus issues is for 
the most part water forced up from the soil. It is equally 
plain that the sap, thus collected, has not the normal 
composition of the juices of the plant ; it must be diluted, 
and must be the more diluted the longer and the more rap- 
idly it flows. 

TJlbricht has made partial analyses of the sap obtained 
from the stumps of potato, tobacco and sun-flower plants. 
He found that successive portions, collected separately, 
exhibited a decreasing concentration. In sunflower sap, 
gathered in five successive portions, the liter contained 
the following quantities (grams) of solid matter: 



COMPOSITION- OF THE JUICES. 339 

12 3 4 5 

Volatile substance - 1.45 0.60 0.30 0.25 0.21 

Ash 1.58 1.56 1.18 0.70 0.60 



Total - - - - 3.03 2.16 1.48 0.95 0.81 

The water which streams from a wound dissolves and 
carries forward with it matters, that in the uninjured plant 
would probably suifer a much less rapid and extensive 
translocation. From the stump of a potato-stalk would 
issue by the mere mechanical effect of the flow of water 
substances generated in the leaves whose proper movement 
in the uninjured plant would be downwards into the 
tubers. 

Different kinds of sap. — It is necessary at this point 
in our discussion to give prominence to the fact that there 
are different kinds of sap in the plant. As we have seen, 
(p. 267,) the cross section of the plant presents two kinds 
of tissue, the cellular and vascular. These carry different 
juices, as is shown by their chemical reactions. In the 
cell-tissues exist chiefly the non-nitrogenous principles, 
sugar, starch, oil, etc. The liquid in these cells, as Sachs 
has shown, commonly contains also organic acids and acid- 
salts, and hence gives a blue color to red litmus. In the 
vascular tissue albuminoids preponderate, and the sap of 
the ducts commonly has an alkaline reaction towards test 
papers. These different kinds of sap are not, however, 
always strictly confined to either tissue. In the root-tips 
and buds of many plants (maize, squash, onion) the ^oung 
(new-formed) cell-tissue is alkaline from the preponderance 
of albuminoids, while the spring sap flowing from the 
ducts and wood of the maple is faintly acid. 

In- many plants is found a system of channels (milk- 
ducts) independent of the vascular bundles, which contain 
an opaquCj white, or yellow juice. This liquid is seen to 



340 HOW OEOPS GROW. 

exude from the broken stem of the milk-weed (Asdepias,) 
of lettuce, or of celandine ( CheUdo7iium^ and may be 
noticed to gather in drops upon a fresh-cut slice of the 
sweet potato. The milky juice often differs not more 
strikingly in appearance than it does in taste, from the 
transparent sap of the cell-tissue and vascular bundles. 
The former is commonly acrid and bitter, while the latter 
is sweet or simply insipid to the tongue. 

Motion of the Nutrient Matters of the plant. — The 

occasional rapid j)assage of a current of water upwards 
through the plant must not be confounded with the normal, 
necessary, and often contrary motion of the nutrient mat- 
ters out of which new growth is organized, but is an in- 
dependent or highly subordinate process by which the 
plant adapts itself to the constant changes that are taking 
place in the soil and atmosphere as regards their content 
of moisture. 

A plant supplied with enough moisture to keep its tis- 
sues turgid is in a normal state, no matter whether the 
water within it is nearly free from upward flow or ascends 
rapidly to compensate the waste by evaporation. In both 
cases the motion of the matters dissolved in the sap is 
nearly the same. In both cases the plant developes nearly 
alike. In both cases the nutritive matters gathered at the 
root-tips ascend, and those gathered by the leaves descend, 
being distributed to every growing cell ; and these motions 
are comparatively independent of, and but little influenced 
by, the motion of the water in which they are dissolved. 

The upward floio of sap in the plant is confined to the 
vascular bundles, whether these are arranged symmetri- 
cally and compactly, as in exogenous plants, or distributed 
singly through the stem, as in the endogens. This is not 
only seen upon a bleeding stump, but is made evident by 
the oft-observed fact that colored liquids, when absorbed 
into a plant or cutting, visibly follow the course of the 



MOVEMENTS OF NUTEIENT MATTERS. 341 

vessels, though they do not commonly penetrate the spu'al 
ducts, hut ascend in the sieve-cells of the camhium.* 

The rapid supply of water to the foliage of a plant, 
either from the roots or from a vessel in which the cut 
stem is immersed, goes on when the cellular tissues of the 
bark and pith are removed or interrupted, but is at once 
checked by severing the vascular bundles. 

The proper motion of the nutritive matters in the plant 
— of the salts dissolved from the soil and of the organic 
principles compounded from carbonic acid, water, and 
nitric acid or ammonia in the leaves — is one of slow dif- 
fusion mostly through the walls of imperforate cells, and 
goes on in all directions. New growth is the formation 
and expansion of new cells into which nutritive substances 
are imhihed, but not poured through visible passages. 
When closed cells are converted into ducts or visibly com- 
municate with each other by pores, their expansion has 
ceased. Henceforth they merely become thickened by in- 
terior deposition. 

Moyements of Nutrient Matters in the Bark or Rind. 

— The ancient observation of what ordinarily ensues when 
a ring of bark is removed from the stem of an exogenous 
tree, led to the erroneous assumption of a formal down- 
ward current of " elaborated " sap in the bark. When a 
cutting from one of our common trees is girdled at its 
middle and then placed in circumstances favorable for 
growth, as in moist, warm air, with its lower extremity in 
water, roots form chiefly at the edge of the bark just 
above the removed ring. The twisting, or half-breaking, 
as well as ringing of a layer, promotes the development 
of roots. Latent buds are often called forth on the stems 
of fruit trees, and branches grow more vigorously, by 
making a transverse incision through the bark just below 

* As in Unger's expei-iment of placing a hyacinth in the juice of the poke- 
weed {^Phytolacca,) or in Hallier's observations on cuttings dipped in cherry-juice. 
{Vs. 8t., IX, p. 1.) 



342 



HOW CROPS GROW. 



the point of their issue. 
Girdling a fruit - bearing 
branch of the vine near its 
junction Avith the older wood 
has the effect of greatly en- 
larging the grapes. It is 
well known that a wide 
wound made on the stem of a 
tree heals up by the formation 
of new wood, and commonly 
the growth is most rapid and 
abundant above the cut. 
From these facts it was con- 
cluded that sap descends in 
the bark, and, not being able 
to pass below a wound, leads 
to the organization of new 
roots or wood just above it. 

The accompanj-ing illustration, 
fig, 66, represents the base of a cut- 
ting from an exogenous steua (pear 
or currant) girdled at B and kept for 
some days immersed in water to the 
depth indicated by the line L. The 
first manifestation of growth is the 
formation of a protuberance at the 
lower edge of the bark, which is 
known to gardeners as a callous, C. 
This is an extension of the cellular 
tissue. From the callous shortly 
appear rootlets, i2, which originate 
from the vascular tissue. Rootlets 
also break from the stem above the 
callous and also above the water, if 
the air be moist. They appear like- 
wise, though in less number, below 
the girdled place. 

Nearly all the organic sub- 
stances (carbohydrates, al- 
buminoids, lignin, etc.,) that 




Fig. 66. 



MOVEMENTS OF NTJTEIENT MATTERS. 343 

are formed in a plant are produced in the leaves, 
and must necessarily find their way down to nourish 
the stem and roots. The facts just mentioned demon- 
strate, indeed, that they do go down in the bark. We 
have, however, no proof that there is a downward 
flow of sap. Such a flow is not indicated by a single 
fact, for, as we have before seen, the only current of water 
in the uninjured plant is the upward one which results 
from root-action and evaporation, and that is variable and 
mainly independent of the distribution of nutritive matters. 
Closer investigation has shown that the most abundant 
downward movement of the nutrient matters generated 
in the leaves proceeds in the thin-walled sieve-cells of the 
cambium, which, in exogens, is young tissue common to 
the outer wood and the inner bark — which, in fact, unites 
bark and wood. The tissues of the leaves communicate 
directly with, and are a continuation of, the cambium, and 
hence matters formed by the leaves must move most rapid- 
ly in the cambium. If they pass with greatest freedom 
through the sieve-cells, the fact is simply demonstration 
that the latter communicate most directly with those parts 
of the leaf in which the matters they conduct are organized. 

In endogenous plants and in some exogens {Piper me- 
dium, Amaranthus sanguineus) the vascular bundles con- 
taining sieve-cells pass into the pith and are not confined to 
the exterior of the stem. Girdling such plants does not give 
the result above described. With them, roots are formed 
chiefly or entirely at the base of the cutting, (Hanstein,) 
and not above the girdled place. 

In all cases, without exception, the matters organized in 
the leaves, though most readily and abundantly moving 
downwards in the vascular tissues, are not confined to 
them exclusively. When a ring of bark is removed from 
a tree, the new cell-tissues, as well as the vascular, are in- 
terrupted. Notwithstanding, matters are transmitted 
downwards, through the older wood. When but a narrovj 



344 now CEOPS geow. 

ring of bark is removed from a cutting, roots often appear 
below the incision, though in less number, and the new 
growth at the edges of a wound on the trunk of a tree, 
though most copious above, is still decided below — goes 
on, in fact, all around the gash. 

Both the cell-tissue and the vascular thus admit of the 
transport of the nutritive matters downwards. In the 
former, the carbohydrates — starch, sugar, inulin — the fats, 
and acids, chiefly occur and move. In the large ducts, air is 
contained, excei^t when by vigorous root-action the stem 
is surcharged with water. In the sieve-ducts (cambium) 
are found the albuminoids, though not unmixed with car- 
bohydrates. If a tree have a deep gash cut into its stem, 
(but not reaching to the colored heart-wood,) growth is 
not suppressed on either side of the cut, but the nutritive 
matters of all kmds pass out of a vertical direction 
around the incision, to nourish the ncAV wood above and 
below. Girdling a tree is not fatal, if done in the spring 
or early summer when growth is rapid, provided that the 
young cells, which form externally, are protected from 
dryness and other destructive influences. An artificial 
bark, i. e., a covering of cloth or clay to keep the exposed 
wood moist and away from air, saves the tree until the 
wound heals over.* In these cases it is obvious that the 
substances which commonly preponderate in the sieve- 
ducts must pass through the cell-tissue in order to reach 
the point where they nourish the growing organs. 

Evidence that nutrient matters also pass upwards in 
the bark is furnished, not only by tracing the course of 
colored liquids in the stem, but also by the fact that unde- 
veloped buds perish in most cases when the stem is gir- 
dled between them and active leaves. In the exceptions 
to this rule, the vascular bundles penetrate the pith, and 

* If the freshly exposed wood be rubbed or wiped with a cloth, whereby the 
moist cambial layer (of cells containing nuclei and capable of multiplying) is re- 
moved, no growth can occur. Eatzeburg. 



MOVEMENTS OF KUTEIENT MATTERS. 345 

thereby demonstrate that they are the channels of this 
movement. A minority of these exceptions agam makes 
evident that the sieve-cells are the path of transfer, for, as 
Hanstein has shown, in certain plants (Solanaceas, Asclep- 
iadese, etc.,) sieve-cells penetrate the pith imaccompanied 
by any other elements of the vascular bundle, and girdled 
twigs of these plants grow above as well as beneath the 
wound, although all leaves above the girdled place be cut 
off, so that the nutriment of the buds must come from be- 
low the incision. 

The substances vv'hich are organized in the foliage of a 
plant, as well as those which are imbibed by the roots, 
move to any point where they can supply a want. Car- 
bohydrates pass from the leaves, not only downwards, to 
nourish new roots, but upwards, to feed the buds, flowers, 
and fruit. In case of cereals, the power of the leaves to 
gather and organize atmospheric food nearly or altogether 
ceases as they approach maturity. The seed grows at the 
expense of matters previously stored in the foliage and 
stems (p. 218,) to such an extent that it may ripen quite 
perfectly although the plant be cut when the kernel is in 
the milk, or even earlier, while the juice of the seeds is 
still watery and before starch-grains have begun to form. 

In biennial root-crops, the root is the focus of motion 
for the matters organized by growth during the first year; 
but in the second year the stores of the root are com- 
pletely exhausted for the support of flowers and seed, so 
that the direction of the movement of these organized 
matters is reversed. In both years the motion oi water is 
always the same, viz., from the soil upwards to the leaves.* 

The summing up of the whole matter is that the nutri- 



* The motion of water is always upwards because the soil always contains 
more water than the air. If a plant were so situated that its roots should 
steadily lack Avater while its foliage had an excess of this liquid, it cannot bo 
doubted that then the " sap " would pass down in a regular flow. In this case, 
nevertheless, 'the nutrient matters would take their normal course. 

15* 



346 HOW CKOPS GEOW. 

ent substances in the plant are not absolutely confined to 
any path, and may move in any direction. The fact that 
they chiefly follow certain channels, and move in this or 
that direction, is plainly dependent upon the structure 
and arrangement of the tissues, on the sources of nutri- 
ment, and on the seat of growth or other action. 

§ 3. 
THE CAUSES OF MOTION OF THE VEGETABLE JUICES. 

Porosity of Vegetable Tissues. — ^Porosity is an uni- 
versal property of massive bodies. The word porosity 
implies that the molecules or smallest particles of matter 
are always separated from each other by a certain space. 
In a multitude of cases bodies are visibly porous. In 
many more we can see no pores, even by the aid of the 
highest magnifying powers of the microscope ; nevertheless 
the fact of porosity is a necessary inference from another 
fact which may be observed, viz., that of absorption. A 
fiber of linen, to the unassisted eye, has no pores. Under 
the microscope we find that it is a tubular cell, the bore 
being much less than the thickness of the walls. By im- 
mersing it in water it swells, becomes more transJDarent, 
and increases in weight. If the M-ater be colored by solu- 
tion of indigo or cochineal, the fiber is visibly penetrated 
by the dye. It is therefore porous, not only in the sense 
of having an interior cavity which becomes visible by a 
high magnifying poAver, but likewise in having throughout 
its apparently imperforate substance innumerable channels 
in which liquids can freely pass. In like manner, all the 
vegetable tissues are more or less porous and penetrable 
to water. 

Imbibition of Liquids by Porous Bodies.— Not only do 
the tissues of the plant admit of the access of water into 



CAUSES OF THE MOTION OF JUICES. 347 

their pores, but they forcibly drink in or absorb this liquid, 
when it is presented to them in excess, until their pores 
are full. 

When the molecules of the porous body have freedom 
of motion, they separate from each other on imbibing a 
liquid ; the body itself swells. Even powdered glass or 
fine sand perceptibly increases in bulk by imbibing water. 
Clay swells much more. Gelatinous silica, pectin, gum 
tragacanth, and boiled starch, hold a vastly greater 
amount of water in their pores. 

In case of vegetable and animal tissues, or membranes, 
we find a greater or less degree of expansibility from the 
same cause, but here the structural connection of the 
molecules puts a limit to their separation, and the result 
of saturating them with a liquid is a state of turgidity 
and tension, which subsides to one of yielding flabbiness 
when the liquid is partially removed. 

The energy with which vegetable matters imbibe water 
may be gathered from a well-known fact. In granite 
quarries, long blocks of stone are split out by driving 
plugs of dry wood into holes drilled along the desired line 
of fracture and pouring water over the plugs. The liquid 
penetrates the wood with immense force, and the toughest 
rock is easily broken apart. 

The imbibing power of different tissues and vegetable 
matters is widely diverse. In general, the younger or- 
gans or parts take up water most readily and freely. The 
•sap-wood of trees is far more absorbent than the heart- 
wood and bark. The cuticle of the leaf is often compara- 
tively impervious to water. Of the proximate elements 
we have cellulose and starch-grains able to retain, even 
when air-dry, 10-15° |^, of water. Wax and the solid fats, 
as well as resins, on the contrary, do not greatly attract 
water, and cannot easily be wetted with it. They render 
cellulose, which has been impregnated with them, unab- 
sorbent* 



348 HOW CROPS GROW. 

Those vegetable substances which ordinarily manifest 
the greatest absorbent power for water, are pectin, pectic 
and pectosic acids, vegetable mucilage, bassorin, and al- 
bumin. In the living plant the protoplasmic membrane 
exhibits great absorbent power. Of mineral matters, 
gelatinous silica (Exp. 58, p. 123) is remarkable on account 
of its attraction for water. 

Not only do different substances thus exhibit unlike ad- 
hesion to water, but the same substance deports itself va- 
riously towards different liquids. 

100 parts of dry ox-bladder were found by Liebig to 
absorb during 24 hours : — 

268 parts of pure Water. 
133 " " Saturated brine. 
38 " " Alcohol (84° |„.) 
17 " " Bone-oil. 

A piece of dry leather will absorb either oil or water, 
and apparently with equal avidity. If, however, oiled 
leather be immersed in water, the oil is gradually and 
perfectly displaced, as the farmer well knows from his ex- 
perience with greased boots. India-rubber, on the other 
hand, is impenetrable to water, while oil of turpentine is 
imbibed by it in large quantity, causing the caoutchouc 
to swell up to a pasty mass many times its original bulk. 

The absorbent power is influenced by the size of the 
pores. Other things being equal, the finer these are, the 
greater the force with which a liquid is imbibed. This is 
shown by what has been learned from the study of a 
kind of pores whose effect admits of accurate measure- 
ment. A tube of glass, with a narrow, uniform caliber, is 
such a pore. In a tube of 1 millimeter, (about 0^5 of an 
inch) in diameter, water rises 30 mm. In a tube of -^l mil- 
limeter, the liquid ascends 300 mm., (about 11 inches) ; 
and in a tube of jl^ mm. a column of 3,000 mm. is sus- 
tained. In porous bodies, like chalk, plaster stucco, closely 
packed ashes or starcli, Jamin found that water was 



CAUSES OF THE MOTIO]!^ OF JUICES. 349 

absorbed with force enough to overcome the pressure of 
the atmosphere from three to six times ; in other words — 
to sustain a column of water in a wide tube 100 to 200 ft. 
high. {Comptes Rendns, 50, p. 311.) 

Absorbent power is influenced by temperature. "Warm 
water is absorbed by wood more quickly and abundantly 
than cold. In cold water starch does not swell to any 
striking or even perceptible degree, although considerable 
liquid is imbibed. In warm water, however, the case is 
remarkably altered. The starch-grains are forcibly burst 
open, and a paste or jelly is formed that holds many times 
its weight of water. (Exp. 27, p. 65.) On freezing, the 
particles of water are mostly withdrawn from their adhe- 
sion to the starch. The ascent of liquids in narrow tubes 
whose walls are unabsorbent, is, on the contrary, dimin- 
ished by a rise of temperature. 

Adhesive or Capillary Attraction. — The absorj)tion of 
a liquid into the cavities of a porous body, as well as its 
rise in a narrow tube, are but expressions of the general 
fact that there is an attraction between the molecules of 
the liquid and the solid. In its simplest manifestation 
this attraction exhibits itself as Adhesion, and this term 
we shall employ to designate the kind of force under con- 
sideration. If a clean plate of glass be dipped in water, 
the liquid touches, and sticks to, the glass. On withdraw- 
ing the glass, a film of water comes away with it. If two 
squares of glass be set up together upon a plate, so that 
they shall be in contact at their vertical edges on one side, 
and one-eighth of an inch apart on the other, it will be 
seen, on pouring a little water upon the j^late, that this 
liquid rises in the space between them several inches or 
feet where they are in very near proximity, and curves 
downwards to their base where the interval is large. 

Capillary attractio7i — the common designation of the 
force that causes liquids to rise in fine tubes — is the same 
adhesion which is manifested in all the cases of absorp- 



350 HOW CEOPS GROW. 

tion, which have been alluded to. In many phenomena 
of absorption, however, chemical affinity appears to super- 
vene with more or less vigor. 

Adhesive attraction is not manifested universally be- 
tween solids and liquids, as already hinted. Glass dipped 
in mercury is not touched or wetted by it, and when a 
cajDillary tube is plunged in this liquid, we see no rise, but 
a depression within the bore. A greased glass tube de- 
ports itself similarly towards water. 

Adhesion may be a Cause of Continual Movement un- 
der certain circumstances. When a new cotton wick is 
dipped into oil, the motion of the oil may be followed by 
the eye, as it slowly ascends, until the pores are filled. 
At this moment the adhesive attraction between cotton 
and oil is satisfied, and motion ceases. Any cause which 
removes oil from the pores at the apex of the wick will un- 
satisfy their attraction and disturb the equilibrium which 
had been established between the solid and the liquid. A 
burning match held to the wick, by its heat destroys the 
oil, molecule after molecule, and this process becomes per- 
manent when the wick is lighted. As the pores at the 
base of the flame give up oil to the latter, they fill them- 
selves again from the pores beneath, and the motion thus 
set up propagates itself to the oil in the vessel below and 
continues as long as the flame burns or the oil holds out. 

In this process, the pores, if of the same material and 
of equal size, exert everywhere an equal attraction for 
the molecules of oil. The wick, above, contains indeed 
less oil than below, for two reasons. In the first place, 
gravitation, or the earth's attraction, acts most power- 
fully on the oil below, and secondly, time is required 
for the particles of oil to pass upwards, and they cannot 
reach the summit as raj)idly. as they might be consumed. 
We get a further insight into the nature of this motion 
when w^e consider what happens after the oil has all been 
sucked up into the wick. Shortly thereafter the dimen- 



CAUSES OF THE MOTIOX OF JUICES. 851 

sions of the flame are seen to diminisli. It does not, how- 
ever go out, but burns on for a time with continually de- 
creasing vigor. When the supply of liquid in the porous 
body is insufficient to saturate the latter, there is still the 
same tendency to equalization and equilibrium. If, at 
last, when the flame expires, because the combustion of 
the oil falls below that rate which is needful to generate 
heat sufficient to decompose it, the wick be placed in con- 
tact at a single point, with another dry wick of equal 
mass and porosity, the oil remaining in the first will enter 
again into motion, will pass into the second wick, from 
pore to pore, until equilibrium is again restored and the 
oil has been shared equally between them. 

In case of water contained in the cavities of a porous 
body, evaporation from the surface of the latter becomes 
remotely the cause of a continual upward motion of the 
liquid. 

The exhalation of water as vapor from the foliage of a 
plant thus necessitates the entrance of water as liquid at 
the roots, and maintains a flow of it in the sap-ducts, or 
causes it to pass by absorption from cell to cell. 

Liquid Diifusion. — The movements that proceed in 
plants, when exhalation is out of the question, viz., such 
as are manifested in the stump of a vine cemented into a 
guage, (fig. 43, p. 248,) are not to be accounted for by 
capillarity or mere absorptive force under the conditions 
as yet noticed. To approach their elucidation we require 
to attend to other considerations. 

The particles of many difierent kinds of liquids attract 
each other. Water and alcohol may be mixed together 
in all proportions in virtue of their adhesive attraction. 
If we fill a vial with water to the rim and carefully lower 
it to the bottom of a tall jar of alcohol, we shall find after 
some hours that alcohol has penetrated the vial, and water 
has passed out into the jar, notwithstanding the latter 
liquid is considerably heavier than the former. If the wa- 



352 HOW CKOPS GROW. 

ter be colored by indigo or cherry juice, its motion may 
be followed by the eye, and after a certain lapse of time 
the water and alcohol will be seen to have become uni- 
formly mixed throughout the two vessels. This manifesta- 
tion of adhesive attraction is termed Liquid Diffusion. 

What is true of two liquids likewise holds for two 
solutions, i. e., for two solids made liquid by the action of 
a solvent. A vial filled with colored brine, or syrup, and 
placed ill a vessel of water, will discharge its contents in- 
to the latter, itself receiving water in return ; and this mo- 
tion of the liquids will not cease until the whole is uni- 
form in composition, i. e., until every molecule of salt or 
sugar is equally attracted by all the molecules of water. 

When several or a large number of soluble substances 
are placed together in water, the diffusion of each one 
throughout the entire liquid will go on in the same Avay 
until the mixture is homogeneous. 

Liquid Diffusion may be a Cause of Continual Move- 
ment whenever circumstances produce continual disturb- 
ances in the composition of a solution or in that of a mix- 
ture of liquids. 

If into a mixture of two liquids we introduce a solid 
body which is able to combine chemically with, and solid- 
ify one of the liquids, the molecules of this liquid will be- 
gin to move toward the solid body from all jjoints, and 
this motion Avill cease only when the solid is able to com- 
bine with no more of the one liquid, or no more remains 
for it to unite with. Thus, when quicklime is placed in a 
mixture of alcohol and water, the water is in time com- 
pletely condensed in the lime, and the alcohol is rendered 
anhydrous. 

Rate of Diffusion. — The rate of diffusion varies with 
the nature of the liquids ; if solutions, with their degree 
of concentration and with the temperature. 

Colloids and Crystalloids. — There is a class of bodies 
whose molecules are singularly inactive in many respects, 



CAUSES OF THE MOTION- OF JUICES. 353 

and have, when dissolved in water or other liquid, a very 
low capacity for diffusive motion. These bodies are 
termed Colloids^ and are characterized by swelling up or 
uniting with water to bulky masses (hydrates) of gelati- 
nous consistence, by inability to crystallize, and by feeble 
and poorly-defined chemical affinities. Starch, dextrin, 
the gums, the uncrystallized albuminoids, pectin and pectic 
acid, gelatin (glue), tannin and gelatinous silica, are col- 
loids. Opposed to these, in the properties just specified, 
are those bodies which crystallize^ such as saccharose, glu- 
cose, oxalic, citric, and tartaric acids, and the ordinary 
salts. 

Other bodies which have never been seen to crystallize 
have the same high diffusive rate ; hence the class is term- 
ed by Graham Crystalloids.\ 

Colloidal bodies, when insoluble, are capable of imbib- 
ing liquids, and admit of liquid diffusion through their 
molecular interspaces. Insoluble crystalloids are, on the 
other hand, impenetrable to liquids in this sense. The 
colloids swell up more or less, often to a great bulk, from 
absorbing a liquid : the volume of a crystalloid remains 
unchanged. 

In his st;udy of the rates of diffusion of various sub- 
stances, dissolved in water to the extent of one per cent 
of the liquid, Graham found the following 

APPROXIMATE TIMES OF EQUAL DIFFUSION. 

Chlorhydric acid, crystalloid, 1. 



Chloride of sodium, 


(( 


21 


Sugar (cane,) 


u 


7. 


Sulphate of magnesia. 


(C 


7. 


Albumen, 


colloid. 


49. 


Caramel, 


cc 


98. 



* From two Greek words which si^ify glue-like. 

t We have already employed the word Crystalloid to distinguish the amor- 
phous albuminoids from their modifications or combinations which present the 
aspect of crystals, (p. 107.) This use of the word was proposed by Ntigeli in 
1862. Graham had employed it, as opposed to colloid, in 1801. It will perhaps 
be found that Niigeli's crystalloids are ciystalloid in Graham's sense. 



354 HOW CHOPS GROW. 

The table shows that the diffusive activity of chlor- 
hydric acid through water is 98 times as great as that of 
caramel, (see p. 73, Exp. 29). In other words, a molecule 
of the acid will travel 98 times as far in a given time as 
the molecule of caramel. 

Osmose,* or Membrane Diffusion. — ^When two miscible 
liquids or solutions are separated by a porous diaphragm, 
the phenomena of diffusion (which depend upon the mu- 
tual attraction of the molecules of the different liquids or 
dissolved substances), are complicated with those of im- 
bibition or capillarity, and of chemical affinity. The aji- 
hesive or other force which the septum is able to exert 
upon the liquid molecules supervenes upon the mere dif- 
fusive tendency, and the movements may suffer remarka- 
ble modifications. 

K we should separate pure water and a solution of 
common salt by a membrane upon whose substance these 
liquids could exert no action, the diffusion would proceed 
to the same result as were the membrane absent. Mole- 
cules of water would penetrate the membrane on one side 
and molecules of salt on the other, until the liquid should 
become alike on both. Should the water move faster than 
the salt, the volume of the brine would increase, and that 
of the water would correspondingly diminish. Were the 
membrane fixed in its place, a change of level of the liq- 
uids would occur. Graham has observed that common 
salt actually diffuses into water, through a thin membrane 
of ox-bladder def)rived of its outer muscular coating, at 
very nearly the same rate as when no membrane is inter- 
posed. 

Dutrochet was the first to study the phenomena of 
membrane diffusion. He took a glass funnel with a long 
and slender neck, tied a piece of bladder over the wide 
opening, inverted it, poured in brine until the funnel was 



• From a Greek word meaning impulsion. 



Cx\.USES OF TPIE MOTION OF JUICES. 



355 



filled to the neck, and immersed the bladder in a vessel of 
water. He saw the liquid rise in the narrow tube and fall 
in the outer vessel. He designated the passage of water 
into the funnel as endosmose^ or inward propulsion. At 
the same time he found the water surrounding the funnel 
to acquire the taste of salt. The outward transfer of salt 
was his exosmose. The more general word, Osmose, ex- 
presses both j)henomena ; we may, however, employ Du- 
trochet's terms to designate the direction of osmose. 

Osmometer* — When the apparatus employed by Du- 
trochet is so constructed that the size of 
the narrow tube has a known relation 
to, is, for example, exactly yV that of the 
membrane, and the narrow tube itself is 
provided with a millimeter scale, we 
have the Osmometer of Graham, fig. 67. 
The ascent or descent of the liquid in 
the tube gives a measure of the amount 
of osmose, provided the hydrostatic pres- 
sure is counterpoised by making the level 
of the liquid within and without equal, 
for which purpose water is poured into 
or removed from the outer vessel. 
Graham designates the increase of vol- 
ume in the osmometer vl^ positive osmose, 
or simply osmose, and distinguishes the 
fall of liquid in the narrow tube as nega- 
tive osmose. 




Tig. 67. 



lu the figure, tlie external vessel is intended for the reception of wa- 
ter. The funnel-shaped interior vessel is closed below with membrane, 
and stands upon a shelf of perforated zinc for support. The graduated 
tube fits the neck of the funnel by a ground joint. 

Action of the Membrane. — ^When the membrane itself 
has an attraction for one or more of the substances between 
which it is interposed, then the rate, amount, and even di- 
rection, of diffusion may be greatly changed. 



356 HOW CEOPS GROW. 

Water is imbibed by tbe membrane of bladder much 
more freely than alcohol ; on the other hand, a film of 
collodion (nitro-cellulose left from the evaporation of its 
solution in ether,) is penetrated much more easily by alco- 
hol than by water. If now these liquids be separated by 
bladder, the apparent flow will be towards the alcoliol ; 
but if a membrane of collodion divide them, the more 
rapid motion will be into the water. 

When a vigorous chemical action is exerted upon the 
membrane by the liquid or the dissolved matters, osmose 
is greatly heightened. In experiments with a septum of 
porous earthenware (porcelain biscuit,) Graham found 
that in case of neutral organic bodies, as sugar and alco- 
hol, or neutral salts, like the alkali-chlorides and nitrates, 
very little osmose is exhibited, i. e., the diffusion is not 
perceptibly greater than it would be in absence of the 
porous diaphragm. 

The acids, — oxalic, nitric, and chlorhydric, — manifest a 
sensible but still moderate osmose. Sulphuric and phos- 
phoric acids, and salts having a decided alkaline or acid 
reaction, viz., acid oxalate of potash, phosphate of soda, 
and carbonates of potash and soda, exhibit a still more 
vigorous osmose. For example, a solution of one part of 
carbonate of potash in 1,000 parts of water gains volume 
rapidly, and to one part of the salt that passes into the 
water 500 parts of water enter the solution. 

In all cases where diffusion is greatly modified by a 
membrane, the membrane itself is strongly attacked and 
altered, or dissolved, by the liquids. When animal mem- 
brane is used, it constantly undergoes decomposition and 
its osmotic action is exhaustible. In case earthenware is 
employed as a diaphragm, lime and alumina are always 
found in the solutions upon which it exerts osmose. 

Graham asserts that to induce osmose in bladder, the 
chemical action on the membrane must be different on the 
two sides, and apparently not in degree only, but also in 



CAUSES OF THE MOTION- OE JUICES. 357 

kind, viz., an alkaline action on the albuminoid substance 
of the membrane on the one side, and an acid action on 
the other. The water appears always to accumulate on 
the alkaline or basic side of the membrane. Hence with 
an alkaline salt, like carbonate of potash, in the osmometer, 
and water outside, the flow is inwards ; but with an acid 
in the osmometer, there is negative osmose or the flow is 
outwards, the liquid then falling in the tube. 

Osmotic activity is most highly manifested in such salts 
as easily admit of decomposition with the setting free of 
a part of their acid, or alkali. 

Hydration of the membrane. — It is remarkable that 
the rapid osmose of carbonate of potash and other alkali- 
salts is greatly interfered with by common salt, is, in fact, 
reduced to almost nothing by an equal quantity of this 
substance. In this case it is j) rob able that the physical 
eflfect of the salt in diminishing the power of the membrane 
to imbibe water (p. 348,) operates in a sense inverse to, and 
neutralizes the chemical action of the carbonate. In fact, 
the osmose of the carbonate, as well as of all other salts, 
acid or alkaline, may be due to their effect in modifying 
the hydration'^ or power of the membrane to imbibe the 
liquid which is the vehicle of their motion. Graham sug- 
gests this view as an explanation of the osmotic influence 
of colloid membranes, and it is not unlikely that in case 
of earthenware, the chemical action may exert its effect 
indirectly, viz., by producing hydrated silicates from the 
burned clay, which are truly colloid and analogous to ani- 
mal membranes in respect of imbibition. Graham has 
shown a connection between the hydrating eflect of acids 
and alkalies on colloid membranes and their osmotic rate. 

" It is well known that fibrin, albumin and animal mem- 
brane,swell much more in very dilute acids and alkalies, than 
in pure water. On the other hand, when the proportion of 



In case water is employed as the liquid. 



358 HOW CEOPS GROW. 

acid or alkali is carried beyond a point peculiar to each 
substance, contraction of the colloid takes place. The 
colloids just named acquire the power of combining with 
an increased proportion of water and of forming higher 
gelatinous hydrates in consequence of contact with dilute 
acid or alkaline reagents. Even parchment-paper is more 
elongated in an alkaline solution than in pure water. 
When thus hydrated and dilated, the colloids present an 
extreme osmotic sensibility." 

An illustration of membrane-diffusion which is highly 
instructive and easy to j^roduce, is the following : 

A cavity is scooped out in a carrot, as in fig. 68, so that 
the sides remain ^ inch or so thick, and a 
quantity of dry, crushed sugar is introduced ; 
after some time, the previously dry sugar will 
be converted into a syrup by withdrawing 
water from the flesh of the carrot. At the 
same time the latter wiU visibly shrink from 
the loss of a portion of its liquid contents. In 
this case the small portions of juice moistening 
the cavity form a strong solution with the 
sugar in contact with them, into which water diffuses from 
the adjoining cells. Doubtless, also, sugar penetrates the 
jDarenchyma of the carrot. 

In the same manner, sugar, when sprinkled over thin- 
skinned fruits, shortly forms a syrup with the water which 
it thus withdraws from them, and salt packed with fresh 
meat runs to brine by the exosmose of the juices of the 
flesh. In these cases the fruit and the meat shrink as a 
result of the loss of water. 

Graham observed gum tragacanth, which is insoluble in 
water, to cause a rapid passage of water through a mem- 
brane in the same manner from its power of imbibition, 
although here there could be no exosmose or outward 
movement. 

The application of these facts and principles to explain- 




CAUSES OF THE MOTION^ OE JUICES. 359 

ing the movements of the liquids of the plant is ob.vious. 
The cells and the tissues composed of cells furnish pre- 
cisely the conditions for the manifestation of motion by 
the imbibition of liquids and by simple diffusion, as well as 
by osmose. The constant disturbances needful to main- 
tain constant motion are to be found in fully adequate de- 
gree in the chemical changes that accompany the process- 
es of nutrition. The substances that normally exist in the 
vegetable cells are numerous, and they suffer remarkable 
transformations both in chemical constitution and in physi- 
cal properties. The rapidly diffusible salts that are pre- 
sented to the plant by the soil, and the equally diffusible 
sugar and organic acids that are generated in the leaf-cells, 
are, in part, converted into the sluggish, soluble colloids, 
soluble starch, dextrin, albumin, etc., or are deposited as 
solid matters in the cells or upon their walls. Thus the 
diffusible contents of the plant not only, but the mem- 
branes which occasion and direct osmose, are subject to 
perpetual alterations in their nature. More than this, the 
plant grows ; new cells, new membranes, new proportions 
of soluble and diffusible matters, are unceasingly brought 
into existence. Imhibition in the cell-membranes and 
their solid, colloid contents. Diffusion in the liquid con- 
tents of the individual cells, and Osmose between the liq- 
uids and dissolved matters and the membranes, or colloid 
contents of the cells, must unavoidably take place. 

That we cannot follow the details of these kinds of ac- 
tion in the plant does not invalidate the fact of their opera- 
tion. The plant is so complicated and presents such a 
number and variety of changes in its growth, that we can 
never expect to understand all its mysteries. From what 
has been briefly explained, we can comprehend some of 
the more striking or obvious movements that proceed in 
the vegetable organism. 

Absorption and Osmose in Germination. — The absorp- 
fjpn of water by the seed is the first step in Germination. 



860 HOW CROPS GKOAY. 

The coats of the dry seed when put into the moist soil 
imhihe this liquid which follows the cell-walls, from cell 
to cell, until these membranes are saturated and swollen. 
At the same time these membranes occasion or permit os- 
mose into the cell-cavities, w^hich, dry before, become dis- 
tended with liquid. The soluble contents of the cells or 
the soluble results of the transformation of their organized 
matters, diffuse from cell to cell in their passage to the ex- 
panding embryo. 

The quautity of water imbibed by the air-dry seed commonly amounts 
to 50 and may exceed 100 per cent. K. Hoffmann l^as made observations 
on this subject, {Vs. St., VII, p. 50.) The absorption was usually com- 
plete in 48 or 72 hours, and was as follows iu case of certain agricultural 
plants : — 



Jbr cent. 

Mustard 8.0 

Millet 25.0 

Maize 44.0 

Wheat 45.5 

Buckwheat 46.8 

Barley. 48.2 

Turnip 51.0 

Rye 57.7 



Fer cent. 

Oats 59.8 

Hemp. 60.0 

Kidney Bean 96.1 

Horse Bean 104.0 

Pea 106.8 

Clover 117.5 

Beet 120.5 

White Clover 126.7 



Root- Action* — Absorption at the roots is unquestiona- 
bly an osmotic action exercised by the membrane that 
bounds the young rootlets and root-hairs externally. In 
principle it does not differ from the absorption of water 
by the seed. The mode in which it occasions the surpris- 
ing phenomena of bleeding or rapid flow of sap from a 
wound on the trunk or larger roots is doubtless essentially 
as Hofmeister first elucidated by experiment. 

This Jlow proceeds in the ducts and intercommunicating 
wood-cells. Between these and the soil intervenes loose 
cell-tissue surrounded by a compacter epidermis. Osmose 
takes place in the epidermis with such energy as not only 
to distend to its utmost the cell-tissue, but to cause the 
water of the cells to JlUer through their walls, and thus 
gain access to the ducts. The latter are formed in young 



CAUSES OP THE MOTION OF JUICES. 



361 



cambial tissue, and when new, are very delicate in their walls. 
Fig. 69 represents a simple apparatus by Sachs for imi- 
tating the supposed mechanism and process of Root-ac- 
tion. In the fig., g g rej^resents a short, wide, open glass 
tube ; at a, the tube is tied over and securely 
closed by a piece of pig's bladder; it is then 
filled with solution of sugar, and the other end, 
Z*, is closed in similar manner by a piece of parch- 
ment-paper, (p. 59.) Finally a cap of India- 
rubber, K^ into whose neck a narrow, bent glass 
tube, r, is fixed, is tied on over 5. (These join- 
ings must be made very carefully and firmly.) 
The space within t K\& left empty of liquid, and 
the combination is placed in a vessel of water, as 
in the figure. G represents a root-cell whose 

exterior wall (cuti- 
cle,) a,' is less pene- 
trable under pressure 
than its interior, 5/ 
T corresponds to a 
duct of vascular tis- 
sue, and the sur- 
rounding water takes 
the place of that 
existing in the pores 
of the soil. The water shortly penetrates the cell, (7, 
distends the previously flabby membranes, under the ac- 
cumulating tension filters through h into r, and rises in 
the tube ; where in Sachs' experiment it attained a height 
of 4 or 5 inches in 24 to 48 hours, the tube, r, being about 
5 millimeters wide and the area of &, 700 sq. mm. When 
we consider the vast root-surface exposed to the soil, in 
case of a vine, and that myriads of rootlets and root-hau'S 
unite their action in the comparatively narrow stem, wo 
must admit that the apparatus above figured gives us a 
very satisfactory glance into the causes of bleeding. 
16 




Fig. 69. 



362 HOW CROPS GEOW. 

Rapid Motion of Sap in the Stem.— In tlie stem of the 
plant we have commonly a resistance to root-action, so far 
as a flow of liquid is concerned. • The ducts and sieve- 
cells, — in conifers, the wood-cells — though. offering visibly- 
continuous channels for the transmission of juices, are 
nevertheless in most cases extremely small, and while they 
raise liquids with enormous capillary force, they retain 
them with the same force, and continuous motion can only 
be the result of a correspondingly energetic disturbance. 
The root-action which can sustain a column- of mercury 
many inches, or one of water many feet high, in a wide 
tube, is greatly neutralized by capillarity as we ascend the 
stem from the root, or the root from its young extremities. 
Root-action is, however, unsteady in its operation, and 
when it declines from any cause, it is capillarity which acts 
rapidly within the ducts and visible channels to supply 
waste by evaporation. 

Motion of Nutritive or Dissolved Matters: Selective 
Power of the Plant. — ^The motion of the substances that 
enter the plant from the soil in a state of solution and of 
those organized within the plant is to a great degree sep- 
arate from and independent of that which the water itself 
takes. At the same time that water is passing upwards 
through the plant to make good the waste by evaporation 
from the foliage, sugar or other carbohydrate generated 
in the leaves is diffusing against the water, and finding its 
way down to the very root-tips. This diffusion takes place 
mostly in the cell-tissue, and is undoubtedly greatly aided 
by osmose, i. e., by the action of the membranes them- 
selves. The very thickening of the cell- walls by the dep- 
osition of cellulose would indicate an attraction for the 
material from which cellulose is organized. The same 
transfer goes on simultaneously in all directions, not only 
into roots and stem, but into the new buds, into flowers 
and fruit. We have considered the tendency to equaliza- 
tion between two masses of liquid separated from each 



CAUSES OF THE MOTION OF JUICES. 363 

other by penetrable membranes. This tendency makes 
valid for the organism of the plant the law that demand 
creates supply. In two contiguous cells, one of which 
contains solution of sugar, and the other, solution of ni- 
trate of potash, these substances must diffuse until they 
are mingled equally, unless, indeed, the membranes or some 
other substance present exerts an opposing and preponder- 
ating attraction. 

In the simplest phases of diffusion each substance is to 
a certain degree independent of every other. Nitrate of 
potash dissolved in the water of the soil must diffuse into 
the root-cells of a plant if it be absent from the sap of this 
root-cell and the membrane permit its passage. When 
the root-cell has acquired a certain proportion of nitrate 
of potash, a proportion equal to that in the soil-water, the 
nitrate cannot enter it any more. So soon as a molecule 
of the salt has gone on into another ceil or been removed 
from the sap by any chemical transformation, then a mola- 
cule may and must enter from without. 

Silica is much more abundant in grasses and cereals than 
in leguminous plants. In the former it exists to the extent 
of about 25 parts in 1,000 of the air-dry foliage, while the 
leaves and stems of the latter contain but 3 parts. (See 
Wolff's Table in Appendix.) When these crops grow side 
by side, their roots ai'e equally bathed by the same soil- 
water. Silica enters both alike, and, so far as regards it- 
self, brings the cell-contents to the same state of satura- 
tion that exists in the soil. The cereals are able to dispose 
of silica by giving it a place in the cuticular cells ; the 
leguminous crops, on the other hand, cannot remove it 
from their juices; the latter remain saturated, and thus 
further diffusion of silica from without becomes impossi- 
ble except as room is made by new growth. It is in this 
way that we have a rational and adequate explanation of 
the selective power of the plant, as manifested in its de- 
portment towards the medium that invests its roots. The 



364 HOW CEOPS GROW. 

same principles govern the transfer of matters from cell 
to cell, or from organ to organ, within the plant. "Where- 
ever there is unlike composition of two miscible juices, 
diffusion is thereby set np, and proceeds as long as the 
cause of disturbance lasts, provided impenetrable mem- 
branes do not intervene. The rapid movement of water 
goes on because there is great loss of this liquid ; the slow 
motion of silica is a consequence of the little use that arises 
for it in the plant. 

Strong chemical affinities may be overcome by osmose. 
Graham long ago observed the decomposition of alum 
(sulphate of alumina and potash,) by mere diffusion ; its 
sulphate of potash having a higher diffusive rate than its 
sulphate of alumina. In the same manner acid sulphate 
of j)otash, put in contact with water, separates into sul- 
phate of potash and free sulphuric acid. 

We have seen (pp. 170-1) tliat the plant when vegetat- 
ing in solutions of salts, is able to decompose them. It 
separates the components of nitrate of potash — appropriat- 
ing^ the acid and leaving: the base to accumulate in the 
liquid. It resolves chloride of ammonium,— taking up am- 
monia and rejecting the chlorine. The action in these 
cases, we cannot definitely explain, but our analogies 
leave no doubt as to the general nature of the agencies 
that cooperate to such results. 

The albuminoids in their usual form are colloid bodies 
and very slow of diffusion through liquids. They pass a 
membrane of nitrocellulose somewhat (Schumacher) ; but 
can scarcely penetrate parchment-paper. (Graham.) Irt 
the plant they are found chiefly in the sieve-cells and ad- 
joining parts of the cambium. Since for their production, 
they undoubtedly require the concourse of a carbohydrate 
and a nitrate, they are not unlikely generated in the cam- 
bium itself, for here the descending carbohydrates from 
the foliage come in contact with the nitrates as they rise 
from the soil. On the other hand, the albuminoids be- 



CAUSES OF THE MOTION- OP JUICES. 865 

come more diffusible in some of their combinations. 
Schumacher asserts that carbonates and phosphates of the 
alkalies considerably increase the osmose of albumin 
through membranes of nitrocellulose, {PhysiJc der Pflanze^ 
p. 128.) It is probable that those combinations or modi- 
fications -of the albuminoids which occur in the soluble 
crystalloids of aleurone (p. 105,) and haemoglobin (p. 97,) 
are highly diffusible. The fact of their having the form 
of crystals is of itself presumptive evidence of this view, 
which deserves to be tested by experiment. 

Gaseous bodies, especially the carbonic acid and oxygen 
of the atmosphere, which have free access to the intercel- 
lular cavities of the foliage, and which are for the most 
part the only contents of the larger ducts, may be dis- 
tributed throughout the plant by osmose after having been 
dissolved in the sap or otherwise absorbed by the cell- 
contents. 

Inflnence of the Membranes. — The sharp separation 
of unlike juices and soluble matters in the plant indicates 
the existence of a remarkable variety and range of ad- 
hesive attractions. In orange-colored flowers we see upon 
microscopic examination that this tint is produced by the 
united efect of yellow and red pigments which are con- 
tained in the cells of the petals. One cell is filled 
with yellow pigment, and the adjoining one with red, 
but these two colors are never contained in the same^ 
cell. In fruits we have coloring matters of great tinc- 
torial power and freely soluble in water, but they never 
forsake the cells where they aj)pear, never wander into 
the contiguous parts of the plant. In the stems and 
leaves of the dandelion, lettuce, and many other plants, 
a white, milky, and bitter juice is contained, but it is 
strictly confined to certain special channels and never 
visibly passes beyond them. The loosely disposed cells 
of the interior of leaves contain grains of chlorophyll, 
but this substance does not appear in the epidermal cells, 



366 HOW CROPS GEOTV. 

those of tlie stomata excepted. Sachs found that solution 
of indigo quickly entered the roots of a seedling bean, 
but required a considerable time to penetrate the stem, (p. 
239.) Hallier, in his experiments on the absorption of 
colored liquids by plants, noticed in all cases, when leaves 
or green stems were immersed in solution of indigo, or 
black-cherry juice, that these dyes readily passed into and 
colored the epidermis, the vascular and cambial tissue, 
and tbe parenchyma of the leaf-veins, keeping strictly to 
the cell-walls, but in no instance communicated any color 
to the cells containing chloroi^hyll. {Phytopathologies 
Leipzig^ 1868, p. 67.) We must infer that the coloring 
matters either cannot penetrate the cells that are occupied 
with chlorophyll, or else are chemically transformed into 
colorless substances on entering them. 

Sachs has shown in numerous instances that the juices 
of the sieve-cells and cambial tissue are alkaline, while 
those of the adjoining cell-tissue are acid when examined 
by test-paper. {Exp. Phys. der Pflanzen^ p. 394.) 

When young and active cells are moistened with solu- 
tion of iodine, this siibstance penetrates the cellulose 
without producing visible change, but when it acts upon 
the protoplasm, the latter separates from the outer cell- 
wall and collapses towards the center of the cavity, as if 
its contents passed out, without a corresponding endos- 
mose being possible, (p. 224.) 

We may conclude from these facts that the membranes 
of the cells are capable of eifecting and maintaining the 
separation of substances which have considerable attrac- 
tions for each other, and obviously accomplish this result 
by exerting themselves suj^erior attractive or repulsive 
force. 

The influence of the membrane must vary in character 
with those alterations in its chemical and structural consti- 
tution which result from growth or any other cause. It is 
thus, in part, that the assimilation of external food by the 



CAUSES OF THE MOTION OP JUICES. 367 

plant is directed, now more to one class of proximate in- 
gredients, as the carbohydrates, and now to another, as the 
albumifioids, although the supplies of food presented are 
uniform both in total and relative quantity. 

If a slice of red-beet be washed and put into water, the 
pigment which gives it color does not readily dissolve and 
diffuse out oJP the cells, but the water remains colorless for 
several days. The pigment is, however, soluble in water, 
as is seen at once by crushing the beet, whereby the cells 
are forcibly broken open and their contents displaced. 
The cell-membranes of the uninjured root are thus appar- 
ently able to withstand the solvent power of water upon 
the pigment and to restrain the latter from diffusive mo- 
tion. Upon subjecting the slice of beet to cold until it is 
thoroughly frozen, and then placing it in warm water so 
that it quickly thaws, the latter is immediately and deeply 
tinged with red. The sudden thawing of the water with- 
in the pores of the cell-membrane has in fact so altered 
them, that they can no longer prevent the diffusive ten- 
dency of the Digment. (Sachs.) 

§4. 
MECHANICAL EFFECTS OF OSMOSE ON THE PLANT. 

The osmose of water from without into the cells of the 
plant, Avhether occurring on the root-surface, in the buds, 
or at any intermediate point where chemical changes are 
going on, cannot fail to exercise a great mechanical influ- 
ence on the phenomena of growth. Root-action, for ex- 
ample, being, as we have seen, often sufficient to overcome 
a considerable hydrostatic pressure, might naturally be 
expected to accelerate the development of buds and young 
foliage, especially since, as common observation shows, it 
operates in perennial plants, as the maple and grape-vine, 
most energetically at the season when the issue of foliage 
takes place. Experinient demonstrates this to be the fact. 



868 



HOW CEOPS GEOW. 



If a twig be cut from a tree in winter 
and be placed in a room having a summer 
temperature, the buds, before dormant, 
shortly exhibit signs of growth, and if 
the cut end be immersed in water, the 
buds will enlarge quite after the normal 
manner, as long as the nutrient matters 
of the twig last, or until the tissues at 
the cut begin to decay. It is the summer 
temperature which excites the chemical 
changes that result in growth. Water 
is needful to occupy the expanding and 
new-forming cells, and to be the vehicle 
for the translocation of nutrient matters 
from the wood to the buds. Water en- 
ters the cut stem by imbibition or capil- 
larity, not merely enough to replace loss 
by exhalation, but is sucked in by osmose 
acting in the growing cells. Under the 
same conditions as to temperature, the 
twigs which are connected with active 
roots expand earlier and more rapidly 
than. cuttings. Artificial pressure on the 
water which is presented to the latter 
acts with an effect similar to that w^hich 
the natural stress caused by the root- 
power exerts. This fact was demon- 
strated by Boehm {Sitzungsherichte der ' 
Wiener Akad.^ 1863) in an experiment 
which may be made as illustrated by the 
cut, fig. 70. A twig with buds is secured 
by means of a perforated cork into one 
end of a short, wide glass tube, which 
is closed below by another cork through 
which passes a narrow syphon-tube, £. 
The cut end of the twig is immersed in 



CAUSES OF THE MOTION OF JUICES. 369 

water, W] which is put under pressure by pouring mercury 
into the upper extremity of the syphon-tube. Horse- 
chestnut and grape twigs cut in February and March and 
thus treated, — the pressure of mercury being equal to 6-8 
inches above the level, M, — after 4-6 weeks, unfolded their 
buds with normal vigor, while twigs similarly circum- 
stanced but without pressure opened 4-8 days later and 
with less appearance of strength. 

Fr. Schulze {Karsten's Bot. TTnters.^ Berlin^ II, 143) 
found that cuttings of twigs in the leaf, from the horse- 
chestnut, locust, willow and rose, subjected to hydrostatic 
pressure in the same way, remained longer turgescent and 
advanced much farther in development of leaves and flow- 
ers than twigs simply immersed in water. 

The amount of water in the soil influences both the ab- 
solute and relative quantity of this ingredient in the plant. 
It is a common observation that rainy spring weather 
causes a rank growth of grass and straw, while the 
yield of hay and grain is not correspondingly increased. 
The root-action must operate with greater eflect, other 
things being equal, in a nearly saturated soil than in one 
which is less moist, and the young cells of a plant situated 
in the former must be subjected to greater internal stress 
than those of one growing in the latter — must, as a con- 
sequence, attain greater dimensions. It is not uncommon 
to find fleshy roots, especially radishes which have grown 
in hot-beds, split apart lengthwise, and Hallier mentions 
the fact of a sound root of petersilia splitting open after 
immersion in water for two or three days. {Phytopathol- 
ogies p. 87.) This mechanical eflect is indeed commonly 
conjoined with others resulting from abundant nutrition, 
but increased bulk of a plant without corresponding in- 
crease of dry matter is doubtless in great part the conse- 
quence of large supplies of water to the roots and its vig- 
orous osmose into the expanding plant. 

16* 



370 



HOW CKOPS GROW. 



DIRECTION OF VEGETABLE GROWTH. 

One of the most obvious peculiarities of. vegetation is 
that the roots and stems of plants manifest more or less 
regular and often opposite directions of growth. Hoots, 
in general, grow downwards ; stems, in general, upwards, 
though this is by no means a universal rule, both roots 
and stems oftentimes manifesting either tendency in dif- 
ferent points or at different times of their growth. 

Sachs describes the following: mode of observinsj the 
directive tendency of root and stem. 

JE^ fig. 71, is a glass flask containing some water; it is 
closed above by a cork from 
which a young seedling is 
suspended by means of a 
wire. The flask stands upon 
a plate of sand, and it is 
shielded from the light by a 
paste-board cover, JR^ the 
lower edge of which is forced 
down into the sand. The 
water in the flask keeps the 
enclosed air in a moist 
state. In the experiment, a 
sj^routed nasturtium seed 
{Tropmolum, majus) having 
a perfectly straight descend- ' 
ing radicle, was placed at 
night in the apparatus with 
the radicle pointing upwards ^^^* '^^• 

and the plumule downwards. The next morning the 
seedling had the appearance of the figure. During the 
night the tip of the root curved over and the plumule 
sensibly raised itself. By continuing a similar experiment 




CAUSES OF THE MOl'ION OF JUICES. 371 

for a week or more, the rootlet will grow down into the 
water and the stem will reach the cork. As often as the 
position of the seedling is reversed, so often the root and 
stem will reverse the direction of their growth. This ex- 
periment being carried on in total darkness, save during 
the short intervals necessary for observation, the directive 
tendency is shown to be independent of the action of light. 

Causes of Directive Power.— The direction of growth 
in plants appears to be for the most part the consequence 
of the action either of gravitation simply, as in those 
parts which extend directly downwards, or of internal 
tension overcoming gravitation, as in the parts which grow 
vertically upwards, or lastly of a combination (resultant) 
of the two forces in the parts which extend in the inter- 
mediate directions. 

The parts of a plant, whether the individual cells or ag- 
gregates of cells, are either in a state of tension greater or 
less and varying at different times, or they are entirely 
passive. 

In general, tension prevails in most parts of common 
plants ; the full-formed roots, stems, leaves, etc., maintain 
their relative positions against opposing forces, and when 
bent, recover themselves with more or less elasticity and 
completeness. 

There are, however, points where tension is absent or 
equally exerted towards all sides, and is hence unable to 
give direction to growth. This may be the case where 
the tissue, consisting exclusively of newly-formed and im- 
mature cells, having delicate walls, possesses but little 
firmness, but is plastic like a semifluid substance. In such 
a condition of growth the cells follow the stress of gravi- 
tation or of any external force that may be accidentally 
applied. 

Influence of Gravitation. — Most young roots are in 
this passive condition near the tips in the region where 



372 HOW CROPS GROW. 

their elongation occurs. The new growth at these points 
simply obeys the attraction of the earth like any other 
limp or yielding mass, and a root made to grow on a 
horizontal plate of glass, for example, is pushed along by 
the expansion of its young cells and the formation of new 
ones until it reaches the edge, when the tip inclines down- 
ward as a wet string would do. If, however, as many 
times happens, the yielding tissue of new cells is partially 
or entirely enveloped by the more rigid root-cap, the 
downward tendency may be overcome to a corresj^onding 
degree. In this case the tip keeps more or less closely 
the direction already given to the root, resembling in its 
growth a half melted substance protuded from a tube and 
stiffening as it issues. The passive section of the root is 
translated forward as the root itself extends ; the cells that 
to-day yield to the gravitating force, to-morrow become 
so rigid and firmly grown to each other as to resist the 
tendency of this force to coerce them to a vertical, while 
new cells are developed beyond, which conform to the 
gravitating tendency. 

Internal Tension. — ^In the upward-growing stem the 
different parallel and concentric tissues, viz., the cuticle, 
the cell-tissue of the rind, the Avood-cells and ducts, and 
the pith, exist in a state of unequal tension. 

This is shown by well-known facts. If a hollow, suc- 
culent stem, like that supporting a dandelion blossom, be 
cut lengthwise, the parts curve away from each other, 
thus, ) (, and may by a little assistance be rolled together 
in flat coils. The same separation of the halves may be 
observed in any succulent stem, provided it be fresh and 
turgid. It is plain then that the pith-cells of the growing 
stem are compressed by the cuticle ; in other words the 
pith-cells are in a state of tension, while the cuticular cells 
are passively stretched by this interior strain. Closer in- 
vestigation indicates that the matter is somewhat compli- 
cated. If we strip off the " skin," from a stalk of garden 



CAUSES OF THE MOTlOlf OF JUICES. 6t6 

rhubarb (pie-plant,) we shall notice that it curves to a coil 
or spiral. This skin consists of the true cuticle with a 
coating of cell-tissue adhering. The tension of the latter 
and the passivity of the former occasion the curvature. 
Further dissection demonstrates that in general the cuti- 
cle, the wood-cells, and the vascular bundles, are passive, 
while the cell-tissues of the rind and pith, and the corre- 
sponding cell-tissues of the leaves, are tense. 

It follows from these considerations that the length of a 
fresh growing stem must be different from the length of 
its parts when separate from each other. K we divide a 
succulent stem lengthwise, into the pith, the wood and 
the rind or the corresponding parts, and accurately 
measure them, we shall find in fact that they differ as to 
length from each other and from the stem as a whole. 
The pith, when the wood is cut away, elongates, the wood 
shortens, the rind shortens still more. In the original 
stem the cell-tissue being united to the vascular, stretches 
the latter and is at the same time restrained by it. On 
their being cut apart, the one is free to extend and the 
other to shorten. Sachs gives the following comparative 
measurements of the stem of a tobacco plant, and of its 
parts after separation— the length of the stem being as- 
sumed as 100 : 

Entire stem 100 

Rind 94.1 

Wood . . - - - 98.5 

Pith 102.9 

Causes of Tension. — This tense condition of the con- 
siderably developed stem depends partly upon the unequal 
nutrition of the different tissues. Those parts, in fact, ex- 
ert tension in which rapid growth— cell-multiplication— is 
taking ^Ucq. In the simple cell similar tension may exist, 
caused by the tendency of the formative layer to expand 
beyond the limits of the cell-wall. Another cause of 
tension is the different imbibmg and osmotic power of the 



374 HOW CEOPS GEOW. 

tissues for sap. When a fresh stem or leaf loses a few 
per cent of water, it becomes flabby and, except so far as 
supported by indurated woody-tissue, has no self-sustaining 
power and droops from an upright direction. On dissect- 
ing the flabby stem lengthwise, the halves no longer curve 
apart, and the tension noticed in the fresh stem does not 
exist. The water being restored through the root, the 
normal turgor and original position are both recovered. 
In the cell-tissue, the cells themselves, so long as tension 
manifests itself, are fully occupied and distended with sap, 
and contain a highly osmotic protoplasm ; the vascular 
tissues being the result of age and alteration in the cell- 
tissue, are therefore more rigid in their walls and less 
sensitive to mechanical strain. 

Upward Growth. — If a stem whose terminal parts are 
in a state t>f highly unequal tension be brought into a 
horizontal position, it will be found that as it makes new 
growth the tip curves upward until it becomes vertical. 
This is due to the fact that while the whole growing part 
elongates, the under side extends most rapidly. Hof- 
meister has demonstrated that this curvature is not the 
result of increased tension in the active cell-tissue of the 
lower longitudinal section of the stem, but of increased 
extensibility on the part of the cuticular and vascular tis- 
sues of that region, for on removing the entire cuticle 
from a curved onion-stalk the curvature was not increased 
but diminished. 

The question now arises, why do the passive parts of 
the under side of the stem that is out of the vertical ad- 
mit of greater expansion by the stress of the rapidly 
growing tissues, than those of the upper? The only 
cause hitherto assigned is the action of gravitation on the 
juices of the tissues. In a stem inclined from the verti- 
cal, the cells of the lower side experience not only the 
general pressure of the water which renders the whole 
turgid, but, in addition, they sustain a portion of the 



CAUSES OF THE MOTION OF JUICES. 875 

weight of the liquid in the cells above them. In other 
words, they are subject not only to the equal hydraulic 
pressure originating in the roots, but also to a slight hy- 
drostatic pressure from the overlying cells. This pro- 
duces the greater extension of the lower passive tissues, 
and accounts for the curvature upward. When the stem 
becomes vertical the hydrostatic pressure is equal on both 
sides of the stem, and the latter is accordingly maintained 
in that position. (Hofmeister, Sachs.) 

Effect of Light* — Besides the influence of gravitation 
and of interior tension, that of the solar light must be re- 
garded, as it assists largely in producing the more com- 
plex phenomena of direction in the growth of plants. 
The explanations already given refer to the plant when 
unaffected by light. As is well known, the stems, leaves 
and roots of plants, when growing where they are un- 
equally illuminated, as in a window, in most cases curve or 
turn towards the light. More rarely is curvature away 
from the light observed, as in case of the stems of ivy, 
{Hedera helix) ^ and the young rootlets of the mistletoe, 
( Viscum album). The common nasturtium, [Tropceolum 
majus), exhibits in its young stems inclination towards, 
in its older stems inclination away from, the light. Its 
leaves turn always towards, its roots growing in water 
often curve towards, often away from the light. 



APPENDIX. 

TABLE I 



Composition of the Ash of Agkiculttjral Plants and Products 
giving- the Average of all ti'ustwortliy Analyses published up to 
August, 1865, by Professor Emil "Wolff, of the Koyal Academy of 
Agriculture, at Hohenheim, Wirfcemberg.* 







=0 


"fe. 






•S 




^?s 


■g. 




<»5 


^ 


SuMance. 




1^ 


1 


1 


1 


1 


P 


|| 


1 


§ 



I.— MEADOW HAY AND GRASSES. 



lIMeadow hay 

2j Young grass 

SjDeadripe hay 

4 Rye grass in flower.. 

5 Timothy 

Other sweet grasses. 



Oats, heading out 

" in flower... 

Barley, heading out 

' ' in flower 

Winter wheat, heading out.. 

" " in flower 

Winter Rye, heading out 

Green Cereals, lighit 

" "• heavy 

Hungarian millet, green, I 
(Panicum germ.) j 



13 


7.78 


25.6 


7.0 


4.9 


11.6 


6.2 


5.1 


29.6 


1 


9.33 


56.2 


1.8 


2.8 


10.7 


10.5 


4.0 


10.3 


1 


7.73 


7.6 


2.9 


8.4 


12.9 


4.4 


0.7 


63.1 


4 


7.10 


24.9 


4.2 


2.1 


7.5 


7.8 


8.8 


39.6 


8 


7.01 


28.8 


2.7 


8.7 


9.4 


10.8 


8.9 


35.6 


89 


7.27 


38.0 


1.8 


2.6 


5.5 


7.8 


4.4 


37.6 


6 


9.46 


41.7 


4.4 


8.5 


7.0 


8.8 


3.4 


27.9 


7 


7.28 


39.0 


8.8 


3.2 


6.7 


8.3 


2.7 


38.2 


^ 


8.98 


38.5 


1.7 


2.9 


7.0 


10.1 


2.9 


81.2 


5 


7.04 


26.2 


0.6 


3.1 


6.0 


9.8 


2.9 


4S.0 


2 


9.78 


84.7 


1.9 


1.5 


4.9 


7.4 


2.8 


41.9 


8 


fi.99 


25.7 


0.5 


2.2 


3.1 


7.8 


1.9 


56.8 


1 


5.42 


as. 6 


0.8 


8.1 


7.4 


14.7 


1.6 


82.0 


5 


7.20 


29.6 


1.5 


3.9 


6.6 


9.1 


4.1 


41.4 


5 


9.21 


35.6 


3.4 


4.7 


8.3 


8.1 


4.8 


30.0 


2 


7.23 


37.4 


... 


8.0 


10.8 


5.4 


3.6 


29.1 



n.— CLOVER AND FODDER PLANTS. 



17 



Red clover 

a. 15-25 percent potash. 

b. 25-35 " 

c. 35-50 " " 

White clover 

Lucern 

Esparsette 

Swedish clover 

Anthyllls vidneraria 

Green Vetches 

Green pea, in flower. . . 
Green rape, young 



56 


6.72 


84.5 


1.6 


12.2 


84.0 


9.9 


3.0 


2.7 


15 


6.01 


20.8 


1.9 


18.2 


39.7 


9.4 


3.8 


1.2 


23 


6.74 


29.8 


1.6 


11.8 


,85.6 


10.6 


8.0 


2.7 


18 


7.19 


46.3 


1.4 


7.8 


27.3 


9.2 


2.2 


2.5 


2 


7.16 


17.5 


7.8 


10.0 


32.2 


14.1 


8.8 


4.5 


7 


7.14 


25.3 


1.1 


5.8 


48.0 


8.5 


6.1 


2.0 


2 


5.89 


89.4 


1.7 


5.8 


32.2 


10.4 


8.3 


4.0 


2 


5.53 


83.8 


1.5 


15.3 


81.9 


10.1 


4.0 


1.2 


1 


5.60 


10.3 


4.5 


4.6 


68.9 


7.0 


1.6 


2.9 


2 


8.74 


42.1 


2.9 


6.8 


26.8 


12.8 


8.7 


1.8 


1 


7.40 


40.8 


0.2 


8.2 


28.7 


13.2 


3.5 


2.6 


5 


8.97 


32.3 


3.8 


4.5 


23.1 


8.7 


16.3 


3.2 



8.0 
2.0 
5.7 
5.4 
5.0 
4.1 
4.4 
4.0 
5.6 
3.5 
5.3 



4.3 
5.6 

6.4 



3.7 
5.4 
2.9 
3.2 
3.2 
1.9 
3.0 
2.8 
0.2 
3.1 
1.8 
7.6 



* From Prof. Wolff's Mitttere Zusammemetzung der Asche, alter land- und 
forstwirtlischaftlichein, wicMigen Stoffe., Stuttgart, 1865. ""The above Table being 
more complete and in most particulars more exact than the author's means of 
reference enable him to construct, and being moreover likely to be the basis of 
calculations by agricultural chemists abroad for some years to come, has been 
reproduced here literally. The references and important explanations accom- 
panying the original, want of space precludes quoting. Li the table, oxide of 
iron, an ingredient normally present to the extent of less than one per cent, is 
omitted. Chlorine is often omitted, not because absent from the plant, but from 
uncertainty as to its amount. Carbonic acid is also excluded in all cases for the 
sake of uniformity and facility of comparison. 



APPENDIX. 



Composition of the Ash of Agkicultxjkal Plants 


AKI 


► Products. 


^ 


Substance. 


i 




i 


1 


1 
1 


1 


s 


1^ 


1 


1 



m 



26 



29 



34 



37 



4G 



70 



Potatoes 

Artichokes 

Beets 

Sugar l)eets 

Turnips 

Turnips* 

Ruta-bagas 

Carrots 

Chicory 

Sugar beet-heads t. 



.— EOOT CROPS. 












31 


3.74 


59.8 


1.6 


4.5 


2.3 


19.1 


6.6 


2.3 


1 


5.16 


65.4 




2.7 


3.5 


16.0 


3.2 




15 


6.86 


53.1 


14.8 


5.1 


4.6 


9.6 


3.3 


3.3 


44 


4.35 


49.4 


9.6 


8.9 


6.3 


14.8 


4.7 


3.5 


15 


8.28 


39.3 


11.4 


3.9 


10.4 


13.3 


14.3 


2.4 


2 


7.20 


50.6 


3.8 


2.1 


13.4 


17.4 


6.0 


1.1 


2 


7.68 


51.2 


•6.7 


2.6 


9.7 


15.3 


8.4 


0.5 


10 


6.27 


36.7 


22.1 


5.3 


10.7 


12.5 


6.4 


2.0 


7 


5.21 


40.4 


7.7 


6.3 


8.7 


14.5 


9.2 


6.1 


1 


4.03 


29.6 


24.4 


11.0 


9.1 


12.8 


7.6 


2.0 



2.8 
2.4 
6.6 
2.0 
4.1 
6.4 
5.1 
3.2 
3.7 
0.5 



IV.— LEAVES AND STEMS OF ROOT CROPS. 

Potatoes, August 

" October 

Beets 

Sugar beets 

Turnips 

Kohl-rabi 

Carrots 

Chicory 

Cabbage 

Cabbage stalk 

v.— REFUSE AED MANUFACTURED PRODUCTS. 



3 


8.92 


14.5 


2.7 


16.8 


39.0 


6.1 


5.6 


8.0 


1 


5.12 


6.3 


0.8 


22.6 


46.2 


5.5 


5.5 


4.2 


6 


15.96 


29.1 


21.0 


9.7 


11.4 


5.1 


7.4 


4.8 


7 


17.49 


22.1 


16.8 


18.3 


19.7 


7.4 


8.0 


3.1 


16 


13.68 


22,9 


7.8 


4.5 


32.4 


8.9 


9.9 


3.8 


1 


16,87 


14 4 


3,9 


4.0 


33.3 


10.4 


11.7 


10.5 


7 


13.57 


14.1 


23.1 


4.6 


33.0 


4.7 


7.9 


5.6 


1 


12.46 


60.0 


0.7 


3.2 


14.3 


9.0 


9.0 


1.0 


2 


10.81 


48.6 


3.9 


3.3 


15.3 


15.8 


8.5 


1.2 


1 


6.46 


43.9 


5.5 


4.1 


11.3 


20.9 


11.8 


1.1 



Sugar beet cake 

a. Common cake 

b. Residue of maceration.... 

c. Residue from Centrifugal 

machine 

Beet molasses 

Molasses slump % 

Raw beet sugar 

Potato slumpt 

Potato fiber II 

Potato juice 1 

Potato skins § 

Fine wheat flour 

Rye flour 

Barley flour 

Barley dust ** 

Maize meal 

Millet meal 

Buckwheat grits 

Wheat bran..... 

Rye bran 

Brewer's grains 

Malt 

Malt sprouts 

Wine grounds 

Grape skins 

Beer 

Grape must 

Rape cake 



7 


3.15 


2 


3.03 


2 


3.53 


1 


3.11 


3 


11.28 


1 


19.02 


1 


1,43 


1 


11.10 


4 


0.99 


2 


23.45 


3 


9.59 


1 


0.47 


1 


1.97 


1 


2.33 


1 


5.62 


1 




1 


1.35 


2 


0.72 


1 


0.43 


1 


8.22 


2 


5.17 


1 


2.78 


1 


6.56 


1 


4.60 


2 


4.04 


1 




6 




2 


6.59 



i.O 



45.5 
71.1 



8.4 
12.7 
9.4 



10.5 



89 


8 


0. 


33.3 


28.0 




46.3 


6.6 


8.8 


15.6 




7.6 


69.5 




3.5 


72.0 


0.7 


6.7 


36.0 


0.9 


8.2 


38.4 


1.8 


8.0 


28.8 


2.5 


13.5 


18.9 


1.4 


7.7 


28.8 


3.5 


14.9 


19.7 


2.3 


25.8 


25.4 


5.9 


12.9 


24.0 


0.6 


16.8 


27.0 


1.3 


15.8 


4.2 


0.8 


10.1 


17.3 




8.4 


34.9 




1.4 


53.4 


6.5 


3.2 


49.4 


2.2 


6.1 


37.5 


7.8 


4.9 


62.8 


0.9 


5.6 


24.3 


0.1 


11.5 



5.6 



0.4 



25.3 

27.2 
27.9 

25.3 

6.0 

9 

8.5 
6.2 

47.8 
1.0 
9.6 
2.8 
1.0 
2.8 
2.5 
6.3 

*2'.3 
4.7 
3.5 

11.6 
3.8 
1.5 

15.5 

13.0 
2.2 
4.9 

10.9 



10.2 


3.9 


6.2 


4.8 


12.9 


5.8 




13.0 


6.0 


2.3 





0.9 


13.0 


6.5 


.... 




0.5 


2.1 


0.7 


10.1 


0.1 


1.7 




1.6 




22.9 


0.9 


5.8 


20.0 


7.3 


3.4 


2.1 


23.9 




3.1 


1.3 


16.3 


3.6 


0.1 


7.5 


3.4 


0.4 


2.7 


2.1 


52 








48.3 
47.3 








3.1 






28.9 




20.(1 




45.0 








47.3 


2.7 






4S.1 


1.7 




1.6 


51 .8 




1.1 




47 9 








38.0 


0.8 


32.2 




36.5 




33.2 




21.0 


6.3 


29.5 




15.5 


7.8 




0.5 


20.8 


4.4 


3.5 


0.6 


32.7 




10.2 




17.7 


6.5 


1.3 


0.6 


36.9 


3.3 


8.7 


0.3 



* White turnips in the original, but apparently no special kind. + Probably 
the crowns of the roots, removed in sugar-making. X The residue after ferment- 
ing and distilling off the spirit. || Refuse of starch manufacture, t Undiluted. 
§ From boiled potatoes. ** Refuse in making barley grits. 



378 



HOW CROPS GROW. 



Composition op the Ash of Agricultural Plants and Products. 



Substance. 






v.— REFUSE AND MANUFACTURED PRODUCTS. 



97 



102 
103 
104 
105 
106 
107 
108 
109 
110 
111 
112 
113 



Linseed cake 

Poppy cake 

Walnut cake 

Cotton seed cake. 



1 


6.24 


23.3 


14 


15.9 


8.6 


35.2 


3.4 


6.5 


1 


10.60 


20. S 


4.5 


4.3 


28.1 


37.8 


2.0 


4.8 


1 


5 36 


33,1 




12.2 


6.7 


43.8 


1.2 


1.6 


1 


6.95 


35.4 




4.3 


4.6 


48.3 


1.1 


4.0 



0.2 



Winter wheat . 

Winter rye 

Winter spelt.. 
Summer lye . . . 

Barley 

Oats 

Maize 

Peas 

Field bean 

Garden bean.. 

Buckwheat 

Rape 

Poppy 



Wheat 

Spelt 

Barley 

Oats 

Maize cobs 

Flax seed hulls. 



VI.- 


-STR 


AW. 














12 


4 96 


11.5 


2.9 


2.6 


6.2 


5.4 


2.9 


66.3 


6 


4 81 


18.7 


3.3 


3.1 


7.7 


4.7 


1.9 


58.1 


2 


5.56 


11.2 


0.4 


0.9 


4.8 


6.3 


1.8 


71.4 


3 


5,. 55 


23.4 




2.8 


8.9 


6.5 


2.6 


55.9 


17 


5 10 


21 .6 


4.5 


2.4 


7.6 


4.3 


3.7 


53.8 


6 


5.12 


22.0 


5.3 


4.0 


8.2 


4.2 


3.5 


48.7 


1 


5.49 


35.3 


1.2 


5.5 


10.5 


8.1 


5.2 


38.0 


21 


5.74 


21.8 


5.3 


7.7 


,37.9 


7.8 


5.6 


5.7 


4 


7.12 


44.4 


3.8 


7.8 


23.1 


7.0 


0.2 


5.4 


5 


6.06 


.37.1 


6.0 


5.2 


27.4 


7.8 


3.6 


4.7 


6 


6 15 


46.6 


2.2 


3.6 


18.4 


11.9 


5.3 


5.5 


12 


4 58 


25.6 


10.3 


5.7 


26.5 


7.0 


7.1 


6.7 


1 


7.86 


38.0 


1.3 


6.5 


30.2 


3.5 


5.1 


11.4 



6.1 
13.8 
5.2 

7.7 

12.4 

2.5 



Vn.— CHAFF, ETC. 



1 


10.73 


9.1 


1.8 


1.3 


1.9 


4.3 




81.2 




2 


9.50 


9.5 


0.3 


2.5 


2.4 


7.3 


2.3 


74.2 




1 


14 23 


7.7 


0.9 


1.3 


10.4 


2.0 


3.0 


70.8 




1 


9 22 


13.1 


4,8 


2.6 


8.9 


0.3 


2.5 


.59.9 




1 


0.56 


47.1 


1.2 


4.1 


3.4 


4.4 


1.9 


26.4 




1 


6.62 


31.1 


4.3 


2.8 


29.6 


2.8 


4.8 


17.2 


6.i 



Yin.— TEXTILE PLANTS, ETC. 



Flax Straw 

Rotted flax stems . 

Flax fiber 

Entire flax plant. . 
Entire hemp plant. 
Entire hop plant.. 

Hops 

Tobacco 



8 


3.71 


.36.9 


5.1 


7.1 


22.3 


11.5 


5.3 


6.0 


2 


2.40 


9.0 


4.8 


5.4 


.51.4 


5.9 


3.1 


13.8 


3 


67 


3.3 


3.2 


5.4 


63.6 


10.8 


2.7 


6.2 


2 


4.30 


34.2 


4.8 


9.0 


15.5 


23.0 


4.9 


2.6 


2 


4.60 


18.3 


3.2 


9.6 


4;i.4 


11.6 


2.8 


7.6 


1 


9,87 


26.2 


3.8 


5.8 


16.0 


12.1 


5.4 


21.5 


12 


6 80 


37.3 


2.2 


5.5 


16.9 


15.1 


2.6 


15.4 


7 


24.08 


27.4 


3.7 


10.5 


37.0 


3.6 


3.9 


9.6 



IX.— LITTER. 



Heath 

Broom {Spartium) 

Fern iAs2}idium) 

Scouring rush (Equisetum) . . . 

Sea-weed (Fucus) 

Beech leaves in autumn 

Oak 

Fir " (Pinus sylvestris) 

Red pine leaves {Pinus Picea) 
Reed {Arundophrag.).. . [ria) 
Down grass (Psamma area- 
Sedge ( Carex) 



8 


4.51 


13.2 


5.3 


8.4 


18.8 


5.1 


4.4 


35.2 


2 


2.25 


.36.5 


2.5 


12.4 


17.1 


8.6 


3.5 


10.3 


5 


7,01 


42.8 


4.5 


7.7 


14.0 


9.7 


5.1 


6.1 


2 


23.77 


13.2 


0.5 


2.3 


12.5 


2.0 


6.3 


53.8 


8 


14.39 


14.5 


24.0 


9.5 


13.9 


3.1 


24.0 


1.7 


6 


6,75 


5,2 


0.6 


6.0 


44.9 


4.2 


3.7 


33.9 




4.90 


3.5 


0.6 


4.0 


48.6 


8.1 


4.4 


30.9 




1.40 


10.1 




9.9 


41.4 


16.4 


4.4 


13.1 




5.82 


1.5 




2.3 


15.2 


8.2 


2.8 


70.1 




4.69 


8.6 


0.2 


1.2 


5.9 


2.0 


2.8 


71.5 






29.8 


4.0 


3.8 


16.5 


7.2 


3.6 


18.5 


11 


8.08 


.33.2 


7.3 


4.2 


5.3 


6.7 


3.3 


31.5 




5.30 


36.6 


6.6 


6.4 


9.5 


6.4 


8.7 


10.9 


2 


8.65 


9.7 


10.3 


3.0 


7.2 


6.5 


5.6 


43.3 



114|Rush {Juncus) 

115lBulrush {Scirpm) 

X.— GRAINS AND SEEDS OF AGRICULTURAL PLANTS. 



4.0 

6.4 
5.9 
2.5 
4.6 
3.4 
4.5 



2.1 

2.7 
10.2 

5.7 
10.1 

0.4 

"4'.4 



5.6 

14.2 



116 
117 
118 
119 



Wheat 
Rye..., 
Barley. 
Oats . . 



78 


2,07 


.31,1 


3.5 


12.2 


3.1 


46.2 


2.4 


1.7 


14 


2,03 


,30,9 


1.8 


10.9 


2.7 


47.5 


2.3 


1 5 


,34 


2 55 


21,9 


2,8 


8.3 


2.5 


32.8 


2.3 


27.2 


20 


3.07 


15.9 


3.8 


7.3 


3.8 


20.7 


1.6 


46.4 



APPENDIX. 



379 



Composition of the Asn or Agricultitkal Plants and Products. 



Substance. 



^1 



■^ 



2Q 



s 



5;- 



X.— GRAINS AOT) SEEDS OF AGEICULTURAL PLANTS. 



Spelt with husk. . 

Maize 

Rice with husk... 

" husked 

Millet with husk. 

" husked. 

-™v. Sorghum 

127jBuckwheat . . . 

128 Rape seed 

129 Flax " .... 

130 Hemp " .... 
Poppy " .... 

Madia " 

Mustard " 

Beet " .... 

Turnip " 

Carrot " 

Peas 

Vetches 

Field Beans 

Garden beans 

Lentils 

Lupines 

Clover seed 

Esparsette seed. . . 



120 
121 
123 
123 
124 
125 
126 



131 
132 
133 
134 
135 
136 
13T 
138 
139 
140 
141 
142 
143 
144 



XI.— FRUITS AKD 



2 


4.20 


17.3 


1.8 


5.8 


2.6 


20.0 


8 


1.42 


27.0 


1.5 


14.6 


2.7 


44.7 


3 


7.84 


18.4 


4.5 


8.6 


5.1 


47.2 


3 


0.39 


23.3 


4.8 


13.4 


2.9 


51.0 


2 


4.49 


11.9 


1.0 


8.4 


1.0 


23.4 


1 


1.42 


18.9 


5.8 


18.6 




53.6 


1 


1.86 


20.3 


3.3 


14.8 


1.3 


50.9 


2 


LOT 


23.1 


6.2 


13.4 


3.3 


48.0 


15 


4.24 


23.5 


1.1 


12.2 


13.8 


43.9 


3 


3.65 


32.2 


1.8 


13.2 


8.4 


40.4 


2 


5.48 


20.1 


0.8 


5.6 


23.5 


36.3 


1 


6.12 


13.6 


1.0 


9.5 


35.4 


31.4 


1 




9.5 


11.2 


15.4 


7.7 


55.0 


3 


4.30 


15.9 


5.8 


10.2 


18.8 


39.0 


1 


5.66 


18.7 


17.3 


18.9 


15.6 


15.5 


1 


3.98 


21.9 


1.2 


8.7 


17.4 


40.2 


1 


8.50 


19.1 


4.8 


6.7 


38.8 


15.8 


30 


2.81 


40.4 


3.7 


8.0 


4.2 


36 3 


1 


2.40 


30.6 


10.6 


8.5 


4.8 


38.1 


6 


3.45 


40.5 


1.2 


6.7 


5.2 


39.2 


9 


3.06 


44.1 


2.9 


7.5 


7.7 


30.4 


1 


2.06 


27.8 


9.9 


2.0 


5.1 


29.1 


1 




33.5 


17.8 


6.2 


7.8 


25.5 


3 


4.11 


37.3 


0.6 


12.2 


6.2 


33.5 


1 
OT) i 


4.47 


28.6 
S 01 


2.8 
^ TE 


6.6 

EES 


31.6 
ET 


23.9 
C. 



2.6 


44.0 





1.1 


2.2 




0.6 


0.6 




0.6 


3.0 




0.2 


52.3 




1.5 


'7!5 




2.1 




i.7 


3.6 


1.1 


0.3 


1.1 


1.1 


0;1 


0.2 


11,8 


0.1 


1.9 


3.2 


4:4 


4.7 


2.4 


0.4 


4.2 


2.1 


9.4 


7.1 


0.7 




5.6 


5.3 


3.3 


3.5 


0.9 


2.3 


4.1 


2.0 


1.1 


5.1 


1.2 


2.9 


3.8 


0.8 


0.9 




1.1 


3.3 


6.8 


0.9 


1.8 


4.7 


2.4 


1.3 


3.2 


0.8 


1.1 



145 
146 
147 
148 
149 
150 
151 
152 
153 
154 
155 
156 



157 

158 
159 
160 
161 
162 
163 
164 
165 
166 
167 



Grape seeds 

Alder 

White pine 

Red pine 

Beech nuts 

Acorns. 

Horse-chestnut 

" green husk. 

Apple, entire fruit 

Pear, " " 

Cherry, " " 

Plum, " " 



2 


2.81 


28.6 




8.6 


33.9 


^.0 


2.5 


1.1 


2 


5.14 


37.6 


1.6 


8.0 


30.7 


13.0 


3.4 


3.2 


1 




21.8 


7.1 


16.8 


1.5 


39.7 


.... 


11.7 


1 




22.4 


1.3 


15.1 


1.9 


46.0 




10.4 


1 


3.30 


22.8 


10.0 


11.6 


24.5 


20.8 


2.2 


1.9 


2 




64.5 


0.7 


5.4 


7.0 


16.2 


2.8 


1.1 


2 


2.36 


58.9 




0.5 


11.6 


22.4 


1.4 


0.2 


2 


4.38 


76.4 




1.0 


10.0 


6.3 


1.4 


0.6 


1 




35.7 


26.1 


8.8 


4.1 


13.6 


6.1 


4.3 


1 




54.7 


8.5 


5.2 


8.0 


15.3 


5.7 


1.5 


1 




51.9 


2.2 


5.5 


7.5 


16.0 


5.1 


9.0 


1 




59.2 


0.5 


5.5 


10.0 


15.1 


3.8 


2.4 



XII.— LEAVES OP TREES. 



Mulberry , 

Horse-chestnut, spring., 
" autumn. 

"Walnut, spring , 

" autumn 

Beech, summer 

" autumn , 

Oak, summer , 

" autumn 

Fir, autumn , 

Red pine, autumn 



3 


3.53 


19.6 






5.4 


25.7 


10.2 


0.5 


33.5 


2 


7.17 


38.8 






3.9 


21.3 


23.4 


6.0 


2,9 


1 


7.52 


19.6 






7.8 


40.5 


8.2 


1.7 


13.9 


1 


7.72 


42.7 






4.6 


26.9 


21.1 


2.6 


1.2 


1 


7.01 


26.6 






9.8 


53.7 


4.0 


2.7 


2.0 


2 


4.83 


18.5 


1 


8 


8.6 


36.5 


7.8 


3.1 


15.2 


6 


6.75 


5.2 





6 


6.0 


44.9 


4.2 


3.7 


33.9 


1 


4.60 


33.1 






13.5 


26.1 


12.2 


2.7 


4.4 


1 


4.90 


3.5 





6 


4.0 


48.6 


8.1 


4.4 


30.9 


1 


1.40 


10.1 






9.9 


41.4 


16.4 


4.4 


13.1 


1 


5.82 


1.5 






2.3 


15.2 


8.2 


2.8 


70.1 



Grape 

Mulberry 

Birch 

Beech, body-wood. 



Xlii 


—WOOD. 














8 


2.75 


29.8 


6.7 


6.8 


37.3 


12.9 


2.7 


0.8 


1 


1.60 


6.5 


14.3 


5.7 


57.3 


2.2 


10.3 


3.6 


2 


0.31 


11.6 


5.8 


8.9 


60.0 


8.5 


0.3 


4.8 


2 


0.65 


16.1 


3.4 


10.8 


56.4 


5.3 


1.0 


4.7 



0.3 
0.1 
0.3 



0.5 
1.7 
6.4 
5.6 



1.1 



0.1 
3.8 
4.1 
0.5 
0.8 
1.2 
0.4 
0.1 

■4'.4 



0.8 
4.2 
0.6 
0.1 



5S0 



HOW CKOPS GEOW. 



Composition op the Ash of Agkicultural Plants and Products. 



Substance. 



. 5S 



1^ 






172 
1T3 
174 
175 
176 
177 
178 
179 
180 
181 
182 
183 
184 
185 
186 
187 



Beech, email wood. 

" brush 

Oak, ■body-wood [bark 

" small branches with 
Horse-chestnut twigs, autu'n 
Walnut twigs, autumn. 

Poplar, young twigs 

Willow, " " .... 

Elm, " " .... 

Elm, body-wood 

Linden . 
Apple tree. 
Red pine . 
White pine. 
Fir. 
Larch. 



xni 


—WOOD. 














1 


1.05 


15.2 


2.1 


16.8 


4.S.8 


11.6 


0.7 


6.71 


1 


1.45 


14.1 


2.2 


10.8 


48.0 


12.3 


1.2 


9.8 


2 




10.0 


3.6 


4.8 


73.5 


5.5 


1.4 


1.1 


1 




19.8 




7.5 


54.0 


9.3 


1.6 


3.1 


1 


8..S1 


19,4 




5.2 


51.0 


21.7 




0.7 


1 


2.99 


15.3 




8.1 


55.9 


12.2 


3.2 


2.9 


5 




14.0 


6.4 


7.5 


58.4 


13.1 


1.5 


2.0 


1 




11.4 


5.6 


10.1 


.50 8 


16.4 


3.1 


0.7 


1 




24.1 


2.1 


10.0 


37.9 


9.6 


5.4 


6.2 


1 




21.9 


13.7 


7.7 


47.8 


3.3 


1.3 


3.1 


1 




35.8 


6.0 


4.2 


29.9 


4.9 


5.3 


5.3 


2 


1.29 


12.0 


1.6 


5.7 


71.0 


4.6 


2.9 


1.8 


1 


0.2f5 


5.2 


26.8 


6.2 


47.9 


5.1 


3.0 


2.0 


2 


0.28 


15.3 


9.9 


5.9 


50.1 


5.5 


3.0 


6.0 


6 


0.31 


11.8 


4.6 


9.1 


.50.1 


5.8 


2.3 


15.0 


1 


0.32 


15.3 


7.7 


24.5 


27.1 


3.6 


1.7 


3.6 



188'Birch 1 2 

189,Beech 



Horse-chestnut, young, aut'n 
Walnut, " " 

Elm 

Linden 

Red pine 

White pine 

Fir 



XIV 


.—BARK. 














2 


1,33 


3.8 


5.41 8.2 


45.6 


7.3 


1.3;20.1| 






14.7 


0.4 0.2 


57.9 


0.4 


1.3 


18 




6.57 


24.2 


.... 


4.0 


61.3 


7.0 


1.1 


1 1 




6.40 


11.6 




10.6 


70.1 


5.9 


2 


7 






2.2 


10.1 


3.2 


72.7 


1.6 


0.6 


8.9 






16.1 


5.7 


8.0 


60.8 


4.0 


0.8 


2.3 




2.81 


5.3 


4.2 


4.7 


62.4 


2.6 


1.0 


15.7 




3.30 


8.0 


3.2 


3.0 


69.8 


2.5 


1.6 


8.4 


3 


2.01 


3.0 


1.0 


1.4 


43.7 


8.3 


0.8 


31.1 



0.1 
0.1 
0.2 

lA 
0.3 
0.1 
0.6 
6.7 

i!5 
0.2 
4.0 
0.2 
0.4 
0.6 



1.3 

i'.2 
0.4 

1.2 
0.2 
1.0 
0.1 



APPENDIX. 



381 



TABLE II. 



Composition of Fresh or Air-dry Agricultural Products, giving 
the average quantity of Water, Sulphur, Ash, and Ash-ingredients, 
in 1,000 parts of substance, by Prof, Wolff. 



Svbstance. 









t 



Meadow hay , 

Dead ripe hay 

Red clover 

White clover. . . . , 

Swedish clover 

Lucern 

Esparsette 

Green vetches 

Green oats , 



Meadow grass, in blossom. 

Yonng grass 

Rye grass 

Timothy 

Other grasses 

Oats, beginning to head. . . 

" .in blossom 

Barley beginning to head.. 

'' in blossom 

Wheat, beginning to head. 

" in blossom 

Rye fodder 

Hungarian Millet 

Red clover 

White clover 

Swedish clover 

Lucern 

Esparsette 

Antlujllis vvlneraria 

Green vetches 

" peas 

" rape 



Potato , 

Artichoke 

Beet 

Sugar beet 

Turnip 

White turnip * 

Kohl-rabi 

Carrot 

Sugar beet-heads t. 
CMcory 





I.- 


BAY 


. 












144 


66.6 


17.1 


4.7 


3.3 7.7 


4.1 


3.4 19.7 


5.31 


144 


66.2 


5.0 


1.9 


2.3 8.5 


2.9 


0.5 


41.8 


3.8 


IfiO 


56.5 


19.5 


0.9 


6.9 19.2 


5.6 


1.7 


1.5 


2.1 


160 


60.3 


10.6 


4.7 


6.0 19.4 


8.5 


5.3 


2.7 


1.9 


160 


46.5 


15.7 


0.7 


7.114.8 


4.7 


1.9 


0.6 


1.3 


160 


60.0 


15.2 


0.7 


3.528.8 


5.1 


3.7 


1.2 


1.1 


160 


45.3 


17.9 


0.8 


2.614.6 


4.7 


1.5 


1.8 


1.4 


160 


73.4 


30.9 


2.1 


5.019.3 


9.4 


2.7 


^.3 


2.3 


145 


61.8 


24.1 


2.0 


2.0| 4.1 


5.1 


1.7 


20.5 


2.5 



n.— GREEN FODDER. 

700 
800 
700 
700 
700 
820 
770 
750 



770 
690 
700 
680 
800 
810 
815 
753 
785 
780 
820 
815 
850 

III.- 

750 
800 



23.3 


6.0 


1.6 


1.1 


2.7 


1.5 


1.2 


6.9 


20.7 


11.6 


0.4 


0.6 


2.2 


2.2 


0.8 


2.1 


21.3 


5.3 


0.9 


0.5 


1.6 


1.7 


0.8 


8.4 


21.0 


6.1 


0.6 


0.8 


2.0 


2.3 


0.8 


7.5 


21.8 


7.2 


0.4 


0.6 


1.2 


1.7 


1.0 


8.2 


17.0 


7.1 


0.8 


0.6 


1.2 


1.4 


0.6 


4.7 


16.6 


6.5 


0.6 


0.5 


1.1 


1.4 


0.5 


5.5 


22.3 


8.6 


0.4 


0.7 


1.6 


2.3 


0.7 


7.0 


22.5 


5.9 


0.1 


0.7 


1.4 


2.2 


0.7 


10.8 


22.4 


7.8 


0.4 


0.3 


1.1 


1.7 


0.4 


9.4 


21.7 


5.6 


0.1 


0.5 


0.7 


1.6 


0.4 


12.3 


16.3 


6.3 


0.1 


0.5 


1.2 


2.4 


0.2 


5.2 


23.1 


8.6 




1.9 


2.5 


1.3 


0.8 


6.7 


13.4 


4.6 


0.2 


1.6 


4.6 


1.3 


0.4 


0.4 


13.6 


2.4 


1.1 


1.4 


4.4 


2.0 


1.2 


0.6 


10.2 


3.5 


0.2 


1.6 


3.2 


1.0 


0.4 


0.1 


17.6 


4.5 


0.2 


1.0 


8.5 


1.5 


1.1 


0.4 


11.6 


4.6 


0.2 


0.7 


3.7 


1.2 


0.4 


0.5 


12.3 


1.3 


0.5 


0.6 


8.5 


0.9 


0.2 


0.4 


15.7 


6.6 


0.5 


1.1 


4.1 


2.0 


0.6 


0.3 


13.7 


5.6 




1.1 


3.9 


1.8 


0.5 


0.4 


13.5 


4.4 


6.5 


0.6 


3.1 


1.2 


3.2I 


0.4 



1.9 


0.6 


0.4 


0.4 


1.1 


0.7 


1.1 


0.8 


0.9 


0.7 


0.8 


0.3 


0.7 


0.4 


1.2 


0.5 


0.8 


0.7 


1.2 


0.3 


0.6 


0.5 


■i!5 




0.5 


6.5 


0.4 


0.6 


0.3 




0.3 


0.8 


0.3 




■6'.5 


6.3 


0.2 




1.0 


6.6 



-ROOT CROPS. 



9.4 


5.6 


0.1 


0.4 


0.2 


1.8 


0.6 


0.2 


0.3 


0.2 


10.3 


6.7 




0.3 


0.4 


1.6 


0.3 




0.2 




8.0 


4.3 


1.2 


0.4 


0.4 


0.8 


0.3 


0.2 


5 


0.1 


8.0 


4.0 


0.8 


0.7 


0.5 


1.1 


0.4 


0.3 


0,2 




7.5 


3.0 


0.8 


0.3 


0.8 


1.0 


1.1 


0.2 


0.3 


0.4 


6.1 


3.1 


0.2 


0.1 


0.8 


1.1 


0.4 


0.1 


0.4 




9.5 


4.9 


0.6 


0.2 


0.9 


1.4 


0.8 


0.1 


0.5 




8.8 


3.2 


1.9 


0.5 


0.9 


1.1 


0.6 


0.2 


0.3 


0,1 


6.5 


1.9 


1.6 


0.7 


0.6 


0.8 


0.5 


0.1 


0,1 




10.4 


4.2 


0.8 


0.7 


0.9 


1.5 


1.0 


0.6 


0.4 





* No special variety ? t Crowns of sugar beet roots. 



382 



HOW CEOPS GEOW. 



Composition of Fresh or Air-dry Agricultural Products. 



Substance. 



IV.— LEAVES AND STEMS OF BOOT CROPS. 



Potato tops, end of August. . 
" " first of October. 

Beet tops 

Sugar beet tops 

Turnip tops 

Kohl-rabi tops 

Carrot tops 

Chicorj' tops 

Cabbage heads 

Cabbage stems 



M25 


15 fi 


2 3 


0.4 


2.6 


5.1 


•1.0 


0.9 


1.2 


0.7 


770 


11 8 


7 


1 


2.7 


5.5 


0.6 


0.6 


0.5 


0.4 


907 


14 8 


4.8 


8.1 


1.4 


1.7 


0.8 


1.1 


0.7 


1.7 


897 


18.0 


4.0 


3.0 


3.3 


3.6 


1.3 


1.4 


0.6 


1.0 


898 


14.0 


8.2 


1.1 


0.6 


4.5 


1.3 


1.4 


0.5 


1.2 


850 


25.8 


8.0 


1.0 


1.0 


8.4 


2.6 


3.0 


2.6 


1.0 


808 


26,1 


8.7 


6.0 


1.2 


8.6 


1.2 


2.1 


1.5 


1.9 


850 


18.7 


11.2 


0.1 


0.6 


2.7 


1.7 


1.7 


0.2 


0.3 


8,85 


12.4 


6.0 


0.5 


0.4 


1.9 


2.0 


1.1 


0.1 


0.3 


820 


11.6 


5.1 


0.6 


0.5 


1.3 


2.4 


0.9 


0.2 


0.1 



v.— MANUFACTURED PRODUCTS AND REFUSE. 



Sugar "beet cake 

a. Common cake [machine 

6. Residue from Centrifugal 

c. Residue of maceration 

Beet molasses . . 

Molasses slump * 

Raw beet sugar 

Potato sluD^p * 

Potato flbert 

Potato skins % 

Fine wheat flour 

Rye flour 

Barley flour 

Barley dust || 

Maize meal 

Millet meal 

Buckwheat grits 

Wheat bran 

Rye bran 

Brewer's grains 

Malt 

Dried malt 

Malt sprouts 

Wine-grounds 

Grape skins 

Beer 

Wine 

Rape cake 

Linseed cake 

Poppy cake 

Walnut cake 

Cotton seed* cake 



9 7 


8.6 


0.8 


0.5 


2.5 


1.0 


9 8 


2.8 


1.2 




2.5 


1.2 


5.6 


2.6 


0.5 




1.4 


0.7 


4 1 


1.5 


0.4 


0.5 


1.1 


0.3 


98.1 


66.2 


9.8 


0.4 


5.6 


0.6 


17.7 


15.9 


0.2 




18.7 


4.61 3.8 




1.2 




5 9 


2,7 


0.4 


6.5 


0.4 


1.2 


1.9 


0.3 




0.1 


0.9 


0.5 


67.1 


48.8 


0.5 


4.5 


6.4 


2.3 


4.1 


1.5 


0.1 


0.3 


0.1 


2.1 


16,9 


6.5 


0.3 


1.4 


0.2 


8.5 


20.0 


5.8 


0.5 


2.7 


0.6 


9.5 


49.8 


9.4 


0.7 


8.8 


1.2 


14.4 


9.5 


2,7 


0.8 


1.4 


0.6 


4.3 


11.6 


2.8 


0.3 


3.0 




5.5 


6.2 


1.6 


0.4 


0.8 


0.1 


3.0 


55.6 


18.8 


0.3 


9.4 


2.6 


28.8 


71.4 


19.8 


0.9 


11.3 


2.5 


34.2 


12.0 


0.5 


0.1 


1.2 


1.4 


4.6 


14.6 


2.5 




1.2 


0.5 


5.3 


26.6 


4.6 




2.2 


1.0 


0.7 


59.6 


20.8 




0.8 


0.9 


12.5 


16.1 


8.6 


0.1 


0.5 


2.5 


2.5 


16.2 


8.0 


0.4 


1.0 


2.1 


3.4 


8.9 


1.5 


0.8 


0.2 


0.1 


1.3 


2.8 


1.8 




0.2 


0.2 


0.5 


56.0 


18.6 


0.1 


6.4 


6.1 


20.7 


.55.2 


12,9 


0.8 


8.8 


4.7 


19.4 


95.4 


19.8 


4.8 


4.1 


26.8 


86.1 


46.4 


15.4 




5.7 


3.1 


20.8 


61.5 


21.8 




2.6 


2.8 


29.5 



0.4 
0.5 
0.4 
0.1 
2.0 
0.3 
3.1 
0.4 

6!3 



0.6 



0.1 



0.6 



VI~STRAW. 



Winter wheat. 

Winter rye 

Winter spelt... 
Summer i"ye . . . 

Barley 

Oats 

Maize 

Peas 

Field bean 

Garden bean... 



141 


42.6 


4.9 


1.2 


1.1 


2.6 


2.3 


1.2 


28.2 


154 


40.7 


7.6 


1.3 


1.3 


8.1 


1.9 


0.8 


23.7 


143 


47.7 


5.8 


0.2 


0.4 


2.3 


8.0 


0.9 


;W.1 


148 


47.6 


11.1 




1.8 


4.4 


8.1 


1.2 


26.6 


140 


43.9 


9.8 


2.0 


1.1 


8.3 


1.9 


1.6 


23.6 


141 


41.0 


9.7 


2.3 


1.8 


3.6 


1.8 


1.5 


21.2 


140 


47.2 


16.6 


0.5 


2.6 


5.0 


3.8 


2.5 


17.9 


143 


49.2110.7 


2.6 


3.8 


18.6 


3,8 


2.8 


2.8 


180 


58.4125.9 


2.2 


4.6 


13.5 


4.1 


0.1 


3.1 


150 


51.5 


19.1 


3.1 


2.7 


14.1 


4.1 


1.8 


2.4 



.... 


1.6 




0.9 


.... 


i'.h 




1.7 




3.9 


3.0 


0.7 


8.1 


2.2 


2.7 


2.1 



* Residue from spirit manufacture, t Refuse of starch manufacture, 
boiled potatoes. || Refuse from making barley grits. 



% From 



APPENDIX. 



383 



CoMPOSiTioiir OP Fresh or Air-dry AoRicuLTURAii Products. 



Substance. 









VI.— STRA.W. 



Buckwheat. 

Rape 

Poppy 



ir.o 


51.7 M.l 


1.1 


1.9 95 


6.1 


2.7 


2.8 


4.0 


1W 


38.0 9.7 


3.9 


2.110.1 


2.7 


2.7 


2.6 


4.7 


160 


66.0 25.1 


0.9 


4.3 19.9 


2.3 


3.4 


7.5 


1.7 



VII.— CHAPF. 



Wheat 

Spelt 

Barley 

Oats 

Maize cobs 

Flax seed hulls. 



92.5 


8.4 


1.7 


1.2 


1.9 


4.0 




75.1 


82 7 


7.9 


0.2 


2.1 


2.0 


6.0 


1.9 


61.4 


122.4 


9.4 


1.1 


1.6 


12.7 


2.4 


3.7 


86.7 


79.0 


10.4 


3.8 


2.1 


7.0 


0.2 


2.0 


47.3 


5.0 


2.4 


0.1 


0.2 


0.2 


0.2 


0.1 


1.3 


58.3 


18.1 


2.5 


1.6 


17.2 


1.6 


2.8 


10.0 



VIII 



Flax straw 

Rotted flax stems. . . , 

Flax fiber , 

Entire flax plant 

Entire hemp plant. . , 
Entire hop plant — 

Hops 

Tobacco 



—TEXTILE PLANTS, 


ETC. 






140 


31,9 


11.8 


1.6 


2 3 


8.3 


4.3 


2.0 


2.2 


100 


21.6 


1.9 


1.0 


1.2 


11.1 


1.3 


0.7 


3.0 


ion 


6.0 


0.2 


0.2 


0.3 


3.8 


0.7 


0.2 


0.3 


250 


32.3 


11.3 


1.5 


2.9 


5.0 


7.4 


1.6 


0.8 


300 


28.2 


5.2 


0.9 


2.7 


12.2 


3.3 


0.8 


2.1 


250 


74.0 


19.4 


2.8 


4.3 


11.8 


9.0 


3.8 


15.9 


120 


59.8 


22.3 


1.3 


2.1 


10.1 


9.0 


1.6 


9.2 


180 


197.5 


54.1 


7.3 


20.7 


73.1 


7.1 


7.7 


19.0 



200 


36.1 


4.8 


1.9 


3.0 


6.8 


1.8 


1.6 


12.7 


0.8 




160 


18 9 


6,9 


0.5 


2.8 


3.2 


1.6 


0.7 


1.9 


0.5 




160 


58.9 


2.5.2 


2.7 


4.5 


8.3 


5.7 


3.0 


3.6 


6.0 




140 


204 4 


27 


1.0 


4.7 


25.6 


4.1 


12.9 


110.0 


11.7 




180 


118.0 


17.1 


28.3 


11.2 


16.4 


3.7 


28.3 


2.0 


11.9 




150 


57.4 


3.0 


0.3 


3.4 


25.8 


2.4 


2.1 


19.5 


0.2 




150 


41.7 


1.5 


0.2 


1.7 


20.2 


3.4 


1.8 


12.9 






160 


11.8 


1.2 




1.1 


4.9 


1.9 


0.5 


1.5 


6.5 




160 


48.9 


0.7 




1.1 


7.4 


4.0 


1.4 


34.3 


.... 




ISO 


38 5 


3 3 


0.1 


0.5 


2.3 


0.8 


1.1 


27.5 


.... 




140 


69.5 


23.1 


5.1 


2.9 


3.7 


4.7 


2.3 


21.8 


3.9 




140 


45 6 


16 7 


3 


2.9 


4.3 


2.9 


4.0 


5.0 


6.5 




140 


74.4 


7.2 


7.7 


2.2 


5.4 


4.8 


4.2 


32.2 


3.9 





IX.— LITTER. 

Heath 

Broom {Spartium) 

Fern {Aspidium) 

Scouring rush {Equisetum) 

Sea-weed {Fucus) 

Beech leaves 

Oak leaves 

Fir leaves (Pinus sylvestris 
Red pine leaves (Pinus picea) 
Reed {Arundophrag.) 

Sedge ( Carex) 

Rush {Juticus) 

Bulrush (Scirpus) 

X.— GRAINS AND SEEDS OP AGRICULTURAL PLANTS. 

Wheat 

Rye 

Barley 

Oats 

Spelt, with husk 

Maize 

Rice, with husk 

'' husked 

Millet, with husk 

" husked 

Sorghum 

Buckwheat 

Rape seed 

Flax " 

Hemp " 

Poppy " 

Mustard " — 

Beet " 

Turnip " 

Carrot " 

Peas 

Vetches. 



143 


17.7 


5.5 


0.6 


2.2 


0.6 


8.2 


0.4 


149 


17.3 


5.4 


0.3 


1.9 


0.5 


8.2 


0.4 


145 


21.8 


4.8 


0.6 


1.8 


0.5 


7.2 


0.5 


140 


26.4 


4.2 


1 


1.8 


1.0 


5.5 


0.4 


148 


35.8 


6.2 


0.6 


2.1 


0.9 


7.2 


0.6 


136 


12.3 


3.3 


0.2 


1.8 


0.3 


5.5 


0.1 


130 


69.0 


12.7 


3.1 


5.9 


3.5 


32.6 


0.4 


130 


3.4 


0.8 


0.2 


0.5 


0.1 


1.7 




130 


39.1 


4.7 


0.4 


3.3 


0.4 


9.1 


0.1 


131 


12.3 


2.3 


0.7 


2.3 




6.6 


0.2 


140 


16.0 


4.2 


0.5 


2.4 


0.2 


8.1 




141 


9.2 


2.1 


0.6 


1.2 


0.3 


4.4 


6.2 


120 


37.3 


8.8 


0.4 


4.6 


5.2 


16.4 


1.3 


118 


32.2 


10.4 


0.6 


4.2 


2.7 


13.0 


0.4 


122 


48.1 


9.7 


0.4 


2.7 


11.3 


17.5 


0.1 


147 


52,2 


7.1 


0.5 


5.0 


18.5 


16.4 


1.0 


120 


37.8 


6.0 


2.2 


3.9 


7.1 


14.7 


1.8 


140 


48.7 


9.1 


8.4 


9.2 


7.6 


7.6 


2.0 


120 


35.0 


7.7 


0.3 


3.0 


6.1 


14.1 


2.5 


120 


74.8 


14.3 


3.6 


5.0 


29.0 


11.8 


4.2 


138 


24.2 


9.8 


0.9 


1.9 


1.2 


8.8 


0.8 


136 


20.7 


6.3 


2.2 


1.8 


0.6 


7.9 


0.9 



1.4 



3.6 


0.8 

'i!3 

1.8 



1.5 


1.4 
0.2 


i'.o 




0.7 




3.4 


2.0 


0.2 


4.8 


8.8 





0.3 





1.5 


0.3 




1.7 


5.9 




1.4 


12.3 




1.7 


15.8 






0.3 




1.2 


0.4 






0.1 






20.5 




1.8 


'l.2 


'6*.2 


::;: 


0.4 


0.1 


8.2 


0.4 




1.7 


5.7 


0.1 




1.7 


2.3 




9 


0.2 


10.1 


1.0 


4.6 


0.8 


0.2 




7.8 


4.0 


2.5 


2.7 


0.2 


0.6 


2.4 


0.4 


0.2 





384 



HOW CEOPS GEOW. 



Composition of Fkesh ob Air-dby Ageicultueal Peoducts. 



S2 



X.— GEAmS AND SEEDS OF AGEICULTUEAL PLANTS. 



Field beans 

Garden beans.. 

Lentils 

Lupines 

Clover seed 

Esparsette seed. 



141 


29.6 


12.0 


148 


2fi.l 


11.5 


134 


17.8 


7.7 


i;^8 


MA) 


11.4 


150 


3fi.9 


13.8 


1(50 


37.6 


10.8 



1.5 
2.0 
0.9 
2.7 
2.3 
11.9 



11.6 

7.9 
5.2 
8.7 
12.4 
9.0 



1.5 
1.0 

2.3 
1.7 
1.2 



0.812.? 



2.5 



2.8 



XI.— FEUITS AND SEEDS OF TEEES, ETC. 



Grape seeds 

Alder " 

Beech nuts 

Acorns, fresh 

" dried 

Horse-chestnuts, fresh 

" green husk.. 

Apple, entire fruit 

Pear, " '- 

Cherry, " " 

Plum, " " 



120 


24.7 


7.1 


.. 


2.1 


8.4 


5.9 


0.6 


0.3 


0.1 


140 


44.2 


16.6 


0.7 


3.5 


13.6 


5.7 


1.5 


1.4 




180 


27.1 


6.2 


2.7 


3.1 


6.7 


5.6 


0.6 


0.5 


0.1 


560 


9.6 


6.2 


0.1 


0.5 


0.7 


1.6 


0.2 


0.2 


0.1 


1.58 


18.3 


11.8 


0.1 


1.0 


1.3 


3.3 


0.5 


0.4 


0.3 


492 


12.0 


7.1 




0.1 


1.4 


2.7 


0.2 




0.8 


818 


8.0 


6.1 




0.1 


0.8 


0.5 


0.1 


0.1 


0.4 


840 


2.7 


1.0 


0.7 


0.2 


0.1 


0.4 


0.2 


0.1 




800 


4.1 


2.2 


0.4 


0.2 


0.3 


0.6 


0.2 


0.1 




780 


4.3 


2.S 


0.1 


0.2 


0.3 


0.7 


0.2 


0.4 


0.1 


820 


4.0 


2.4 


... 


0.2 


0.4 


0.6 


0.2 


0.1 





Xn.— LEAVES OP TEEES. 



Mulberry 

Horse-chestnut, spring... 
" autumn. 

"Walnut, spring 

" autumn 

Beech, summer 

" autumn 

Oak, summer 

" autumn 

Fir, autumn , 

Eed pine, autumn 



670 


11.7 


2.3 




0.6 


3.0 


1.2 


0.1 


4.1 




700 


21.5 


8.3 




0,8 


4.6 


5.0 


1.3 


0.6 


0.8 


600 


30.1 


5.9 




2.4 


12.2 


2.5 


0.5 


4.2 


1.2 


700 


23.2 


9.9 




1.1 


6.2 


4.9 


0.6 


0.3 


0.1 


600 


28.4 


7.6 




2.8 


15.3 


1.1 


0.8 


0.6 


0.2 


750 


12.1 


2.2 


0.2 


1.1 


4.4 


0.9 


0.4 


1.8 


0.1 


5.50 


30.5 


1.6 


0.2 


1.8 


13.7 


1.3 


1.1 


10.3 


0.1 


700 


13.8 


4.6 




1.9 


3.6 


1.7 


0.4 


0.6 




600 


19.6 


0.7 


0.1 


0.8 


9.5 


1.6 


0.9 


6.1 




550 


6.3 


0.6 




0.6 


2.6 


1.3 


0.3 


0.8 


0.3 


550 


26.2 


0.4 




0.6 


4.0 


2.1 


0.7 


18.4 





Xin.— WOOD. (AlR-DRT.) 



Grape... 

Mulberry 

Birch 

Beech, body- wood 

" small wood 

" brush 

Oak, body-wood 

" small branches with bark 
Horse-chestnut, young wood 

in autumn 

Walnut 

Apple tree 

Eed pine 

White pine 

Fir 

Larch 



Birch 

Horse-chestnut, young in aut. 
Walnut, " " " 

Eed pine 

White pine 

Fir 



150 


23.4 


7.0 


1.6 


1.6 


8.7 


3.0 


0.6 


0.2 


0.2 


150 


13.7 


0.9 


2.0 


0.8 


7.8 


0.3 


1.4 


0.5 


0.6 


150 


2.6 


0.3 


0.2 


0.2 


1.5 


0.2 


... 


0.1 




150 


5.5 


0.9 


0.2 


0.6 


3.1 


0.3 


0.1 


0.3 




150 


8.9 


1.4 


0.2 


1.5 


4.1 


1.0 


0.1 


0.6 




1.50 


12.3 


1.7 


0.3 


1.3 


5.9 


1.5 


0.1 


1.2 




1.50 


5.1 


0.5 


0.2 


0.2 


3.7 


0.3 


0.1 


0.1 




150 


10.2 


2.0 




0.8 


5.5 


0.9 


0.2 


0.3 




150 


28.1 


5.5 




1.5 


14.3 


5.9 




0.2 


0.4 


150 


25.5 


3.9 




2.0 


14.2 


3.1 


0.8 


0.7 


0.1 


1.50 


11.0 


1.3 


0.2 


0.6 


7.8 


0.5 


0.3 


0.2 


... 


1.50 


2.1 


0.1 


0.6 


0.1 


1.0 


0.1 


0.1 


0.1 


... 


150 


2.4 


0.4 


0.2 


0.1 


1.2 


0.1 


0.1 


0.2 




150 


2.6 


0.3 


0.1 


0.2 


1.3 


0.2 


0.1 


0.4 




150 


2.7 


0.4 


0.2 


0.7 


0.7 


0.1 


0.1 


0.1 


... 



XIV.— BARK. 



150 


11.3 


0.4 


0.6 


0.9 


5.2 


0.8 


0.2 


2.3 


0.2 


1.50 


55.9 


13.5 




2.2 


34.3 


3.9 


0.6 


0.6 


0.7 


1.50 


54.4 


6.3 




5.8 


38.1 


3.2 


0.1 


0.4 


0.2 


150 


23.9 


1.3 


1.0 


1.1 


14.9 


0.6 


0.2 


3.8 


0.1 


1.50 


28.1 


2.3 


0.9 


0.8 


19.6 


0.7 


0.5 


2.3 


0.3 


150 


17.1 


0.5 


0.2 


0.3 


7.5 


1.4 


0.1 


5.3 


... 



APPENDIX. 



385 



TABLE III. 

Proximate Composition of Agricultural Plants and Products, 
giving the average quantities of Water, Organic Matter, Ash, Album- 
inoids, Carbohydrates, etc., Grade Fiber, Fat, etc., by Professors 
Wolff and Knop.* 



Substance. 


1 


1 


.• 


If 


ll 


«! 


1 



HAY. 

Meadow hay, medium quality. 

Aftermath 

Red clover, full blossom 

"• " ripe 

White clover, full blossom — 

Swedish or Alsike clover {Trifolium Jiybridum) 

" clover, ripe *. 

Lucem, young - 

" in blossom 

Sand lucern, early blossom {Medicago intermedia) 

Esparsette, in blossom 

Incarnate clover, do {Trifdium incamatum).. 

Yellow " do (Medicago lupulina) 

Vetches, in blossom 

Peas, " " 

Field spurry, in blossom {Spergula arvensis) — 

" " after blossom 

Serradella, " " {Ornithopus sativus).. 

'■'■ before " 

Italian Rye grass {Lolium italicum) 1 

Timothy {Phleum pratense) 

Early meadow grass (Poa annua) 

Crested dog's tail {Cynosurus cristatus) 

Soft brome grass {Bromus mollis) 

Orchard grass {Dactylis glomerata) 

Barley grass {Hordeum pratense) 

Meadow foxtail (Alopecurus pratemis) 

Oat grass, French rye grass {Arrhenatlverum 

avenaceum) 

English rye grass {Lolium perenne) 

Barter Schwmgel {Festuca f) 

Sweet-scented vernal grass (Anthoxanthum 

odaratum) 

Velvet grass {Holcus lanatus) 

Spear grass, Kentucky Blue grass {Poa 



14.3 

14.3 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

16.7 

14.3 

14. 

14. 

14.3 

14 

14.3 

14. 

14.3 



79.5 
79.2 
77.1 

77.7 

74.8 

75.0 

78.3 

74.6 

76. 

77.2 

77- 1 

76.1 

77.3 

75.0 

76 

73.8 

75.5 

77.7 

75.8 

77.9 

81. 

83. 

80.2 

80.7 

81.1 



14.3 75.: 
14.3 79.! 



14.3 

14.3 
14.3 

14.3 

14. 

14. 

14.3 

14.3 



6.5 

6.2 

5.6 

8.5 

8.3 

5.0 

8.7 

6.4 

6.1 

6.2 

7. 

6.0 

8.3 

7.0 

9.5 

7.8 

5. 

7.5 

7.8 

4.5 

2.4 

5.5 

5.0 

4 

5.3 

6.7 



34. 



.2141 
.5I45. 
13.4 
.4 
14.9 
15.3 
10.2 
19.7 
14.4 
15.2 
13.3 
12.2 
14.6 
14.2 
14.3 
12.0 

7.8 
14.6 
15. 

8.7 

9.7 
10.1 

9.5 
14.8 
11.6 

9.6 
10.6 



32. { 



.7 

.1 

.5 

35.3 



81.0 



80.3 
§0.2 



9.9 11.1 
6.5 10.2 
4.710.4 



78. 
79.8 
78.3 
79.9 



3]30.0 
724.0 
935.8 
348.0 



41, 



25.6 
30.5 
45.0 


40.0 
35.1 
27.1 
33.8 
26.2 
25.5 
25.2 
22.0 

.0 

.9 

.1 
16.9 

7 

25.9 
22.6 
31.0 

.9 
27.2 

.0 



35.3 

38.9 
37.5 

40.2 



39.1 
37.6 
42.6 

42.8 
41.7 



29.4 
30.2 
33.2 

31.2 
33.6 

32.6 
32.6 

30.8 
30.3 

28.7 



2.0 
2.4 
3.2 
2.0 
3.5 
3.3 
2.2 
3.3 
2.5 
3.0 
2.5 
3.0 
3.3 
2.5 
2.6 
3.3 
2.5 
1.5 
1.9 
2.8 
3.0 
2.9 
2.8 
1.8 
2.7 
2.0 
2.5 

2.7 
2.7 



2.9 
3.1 



2.2 
2.6 



Rough meadow grass {Poa trivialis) 

Yellow oat grass {Avena Jlavescens) 

Quaking grass {Briza msdid) 

Average of all the grasses 

T'LandwirthschaftUcJier Kalender, 1867, through Knopfs Agr^ultur-CMmie 
1868 no 715-720. this Table is, as regards water and ash, a repetition ot iable 
II but includes the newer analyses of 1865-7. Therefore the averages of Avater 
and ash do not in all cases agree with those of the former Tables. It gives be- 
sides, the proportions of nitrogenous and non-nitrogenous compounds, 1 e. Al- 
buminoids and Carbohydrates, etc. It also states the averages of Crude hher and 
of Fat, etc. The discussion of the data of this Table belongs to the subjects of 
Food and Cattle-Feeding. They are, however, inserted here, as it is believed 
they are not to be found°elsewhere in the English }^^^frTl?lfT1^t^ 
here signifies the combustible part of the V}^^^'-\\Garbohydratesete^^^^^ 
fat stavch, sugar, pectin, etc., all in fact of Org. matter except Albuminoids and 
Crude fiber -± Crude fiber is impure cellulose obtained by the processes describ- 
eronm-es 60 and 61 -t Fat^^ is the ether-extract p. 94, and contains be- 
sides lat^wax, chlorophyll, and in some cases resins. 
17 



386 



HOW CROPS GEOW. 



Proximate Composition or Agricultural Plants and Products. 



















Substance. 


i 


11 


•§ 
^ 








^ 



STRAW. 

Winter wheat..' 114.8 

Winter rye 114. 3 

Winter spelt il4 " 



Winter bai'ley. 
Summer barley. 



Oat. 



with clover. 



Vetch fodder. 

Pea 

Bean 

Lentil 

Lupine 

Maize 



14.3 
14.3 
14.3 
14.3 



14.3 
14.3 
17.3 

11:1 

14.0 



SO. 2 
82.5 
79.7 
80.2 
78.7 
77.7 
80.7 
79.7 
81.7 
77.7 
79.2 
81.4 
82.0 



r,.^ 


2.0 


30.2 


4S.0 


3.2 


1.5 


27.0 


54.0 


6.0 


2.0 


27.7 


50.5 


5.5 


2.0 


29.8 


48.4 


7.0 


3.0 


32.7 


43.0 


8.0 


6.0 


;w.7 


37.5 


5.0 


2.5 


38.2 


40.0 


6.0 


7.5 


28.2 


44.0 


4.0 


6.5 


;i5.2 


40.0 


5.0 


10.2 


33.5 


U.O 


6.5 


14.0 


27.2 


36.6 


4.4 


4.9 


34.7 


41.8 


4.0 


3.0 


39.0 


40.0 



CHAFF AKD HULLS. 

Wheat 14 . 

14. 



Spelt 

Rye 

Barley . , 

Oat 

Vetch 

Pea 

Bean 

Lupine 

Kape 

Maize cobs. 



3|73.7 
3 77.2 
378.2 
3^72.7 
367.7 
0j77.0 
379.7 
0|77.0 
382.9 
3 77.5 
383.2 



12.0 


4.5 


.33.2 


36.0 


8.5 


2.9 


32.8 


41.5 


7.5 


3.5 


28.2 


46.5 


13.0 


3.0 


38.7 


30.0 


18.0 


4.0 


29.7 


UA) 


8.0 


8.5 


32.5 


36.0 


6.0 


8.1 


36.6 


a^.o 


8.0 


10.5 


29.5 


.37.0 


2.8 


2.5 


47.2 


.33.0 


8.5 


3.5 


40.0 


34.0 


2.8 


1.4 


44.0 


37.8 



Grass, 



GREEN FODDER. 

75.0122. 
69.029. 



before blossom 

after " 

Red clover, before " 

full " 

White " " "• 

Swedish clover, early blossom 

full " 

Lucern, very young 

" in blossom 

Sand lucern, early blossom 

Esparsette, in " [turn) 

Incarnate clover in " {Tnfolium incarna- 
Yellow clover, in blossom {Medicago lupulina).. 
Serradella, " " {OrniUvopus sativm).. 

Vetches, " " 

Peas, " " 

Oats, early blossom 

Rye 

Maize, late end August 

" early" " [cu7n) 

Hungarian millet, in blossom {Panicum germani- 

Sorghum saccharatum 

Sorghum vulgare 

Field spurryin blossom 

Cabbage 

" stumps ..." 

Field beet leaves 

Carrot leaves '.. 

Poplar and elm leaves 

Artichoke stem 

Rape leaves ..'...'. ........ 



83.015 
78.020 
80.517 
85.013 
82.0II6 
81.017 
74.0 24 
78.0 20 
80.9:18 
81.5 16 
80.018 
80.018 
82.016 
81.5 17, 
81.017, 
72.9 25. 
84.314. 

82.2 16. 
65.6132. 
74.012.5. 

77.3 21. 
80.0 18. 



89.0 

90.5 
82.2 
70.0 
50.0 
dry 



2.1 
2.0 
1.5 
1.7 
2.0 
1. 
1.8 
1.7 
2.0 
1.9 
1.5 
1.6 
1.5 
1.3 
1 

1.5 
1.4 
1.6 
1.1 
1.1 
2.4 
0.9 
1.1 
2.0 
1.2 
1.9 
1.8 
3.6 
2.0 
2.7 
^.5 



012.9 
15.0 
.3 
.7 
.5 
.3 
.3 
.5 



8.6 
8.0 
5.7 
6.3 
7.8 
7.0 
6.6 
8.8 
6 

9.0 
7.0 
7.6 
8.2 
8.8 
14.9 



2 
3 

1 
5 
2.5115.3 



10.9 
15.0 



11.9 

10.4 

6.3 

12.2 

4.6 

8.0 

015.5 

3il0.6 

047.5 



7.0 
11.5 
4.5 
8.0 
6.0 
4.5 
6.6 
5.0 
12.5 
9.5 
6.5 
7.5 
6.0 
8.1 
5.5 
5.6 
6.5 
7.3 
5.0 
4.7 
11.5 
7.3 
6.7 
5.3 
2.0 
2.8 
1.3 
3.0 
6.5 
3.4 
8.01 



APPENDIX. 



387 



Proximate Composition of AGRicuiiTuiiAL Plants and Products. 



Substance. 






■^1 






Potato 

Jerusalem Artichoke 

Turnip Chervil? (Koerbelriibe) . . 

Kohl-rabi 

Field beets (about 3 lbs. wei<jht) . 

Su-ar beets.a--2 lbs.) . . . 

Ruta-ba2:as (about 3 lbs.) 

Carrot (about \i lb.) 

Giant carrot (1-2 lbs.) 

Turnips (Stoppelriibe) 

Turnips (Turnipsriibe) 

Parsnip 

Pumpkin 



ROOTS AKD TUBERS. 

95.0;24. 



SO. Oils, 
T6.023. 
SS.OjlO. 
SS.Olll. 
SI. 5 IT, 
ST.Oil-2. 
S5.0:i4. 
87.012. 
91.5 7. 
92.0 7. 
SS.311. 
94.51 4, 

GRAINS AND SEEDS. 

14.6:84, 



Rice 

Winter wheat 

Wheat flour 

Spelt 

Winter 170 ; 

Rye flour 

Winter barley 

Summer barley 

Oats . . 

Maize 

Millet 

Buckwheat 

Vetches 

Peas 

Beans (field) 

Lentils 

Lupines , .*. 

Acorns without shell, dry 

" with " fresh 

Chestnuts without shell, fresh 

]V[adia seed 

Flax seed 

Rape seed 

Hemp seed 

Poppy seed 

Horse chestnut 

REFUSE. 

Sugar beet cake [chine 

" " residue from centrifugal ma- 

" '• " "• " maceration 

Potato slump 

Rj'e slump 

Maize slump 

Molasses slump 

Brewer's grains 

Malt sprouts 

Fresh malt with sprouts 

Dry malt without sprouts 

Wheat bran 

Rye bran 

Rixpe cake 

Linseed cake 

Gold of pleasure cake 



14.4iS3, 
12.6!8G, 
14.8{81, 
14.383, 
14.0lS4, 
14.3183. 
14.3;8;3, 
14.3'82, 
14.4|S3, 

14.0 as, 
i4.o;s;3, 

14.383, 
14.3183, 
14.5 82, 
14.5:82 
14.5;82, 
20.0,78. 
56.0-1:5. 
49.249 
8.4 86. 
12.382 
11.085, 
12.2 83, 
14.7,78, 
3O.0I6S, 



0.9 


2.0 


21.0 


1.1 


1.1 


2.0 


15.6 


1.3 


0.9 


3.2 


17.0 


1.0 


1.2 


2.3 


7.3 


1.2 


0.9 


1.1 


9.1 


0.9 


0.8 


1.0 


15.4 


1 3 


1.0 


1.6 


9.3 


1.1 


1,0 


1.5 


10.8 


1.7 


0.8 


1.2 


9.8 


1.2 


0.8 


0.8 


5.9 


1.0 


0.8 


1.1 


5.1 


1.0 


0.7 


1.6 


8.4 


1.0 


1.0 


1.3 


2.8 


1.0 



70.0 
82.0 
92.6 
94.8 
89.0 
89.0 
92.0 
76.6 

8.0 
47.5 

4.2 
13.1 
12.5 
15.0 77 
11.5 80 
15.0i78 



6.6 



0.3 
0.5 
0.6 
0.2 
0.1 
0.1 
0.1 
0.2 
0.2 
0.1 
0.1 
0.2 
0.1 



0.51 7 
2.0 '13 
0.7|11 
3.910 
2.011 
1.6|10, 
2.3 9 
2.6 9 
3.012 
2.1110, 
3.0!l4, 
2.41 9, 
2.3(27, 
2.5:22 
3.525 
3.0123 
3.5 34 



5;76.5 
67.6 
8i74.1 
0.54.8 
069.2 
572.5 
0:(5o.9 
566.6 
060.9 
068.0 
5 62.1 



59.6 



4.7 22 
5.0 20 
3.9 19 
4.2 16 
7.017 
1.210 



49.2 

52.3 

45.5 

52.0 

3:3.0 

68.8 

36.5 

45.2 
946.0 
5 55.0 
4 55.4 10 
3 55.2 12 
554.71 6 
5158.31 4 



0.9 0.5 
3 

16 



1.0 



1.5 
1.2 
1.5 
2.0 
1.6 
2.5 
2.5 
6.0 
7.0 
3.0 
2.5 
2.7 
2.5 
2.0 
2.6 
6.0 
4.3 
2.3 
2.5 
41.0 

2 37.0 

3 40.0 
133.6 
1 41.0 
0:2.30 



7.428 
7.928 
6.9128 



18.5 

12.2 

4.4 

3.0 

6.8 

7.2 

5.1 

11.1 

0|44.7 

.539 

876 

050.0 

553.5 

333.5 

3141.3 

5137.1 



6.3 


0.2 


3.6 


0.1 


1.4 


0.1 


0,6 


0.1 


1.6 


0.4 


1.3 


1.2 


■6!2 


'i!6 


17.5 


2.5 


4.3 


1.5 


8.0 


2.5 


17.8 


3.8 


15 


3.5 


15.8 


9.0 


11.0 


10.0 


12.5 


8.5 



388 



HOW CEOPS GROW. 



Pboximate Composition of AGRiciiLTUEAii Plants and Product;/. 



Substance. 


h 


II 


1 


II 


j4 

If 


li 


4 
1 



Poppy cake. 
Hemp cake. 
Beechnut cake. 

Beet molasses. 
Potato fiber... 



REFUSE. 



without shells. 



10.0 


81.6 


8.4 


B2.5 


37.7 


10. .5 


85.5 


4..() 


27.0 


36.5 


10.0 


84.8 


5.2 


24.0 


31.3 


12.5 


TO. 8 


7.7 


37.3 


36.9 


1R.7 


72. 5 


10.8 


8.(1 


64.5 


82.6 


17.1 


0.3 


0.8 


15.0 



11.4 


8.1 


22.0 


6. a 


20.5 


7.0 


5.5 


7.5 


i'.s 


o'.j 



COFFEE. TEA. 



CoflFee bean 

Chocolate bean . . 
Black China tea. 
Green " " . 



12 


03.0 


7.0 


10.0 


49.0 


34.0 


11.0 


85.0 


4.0 


20.0 


52.0 


13.0 


15.0 


79.0 


6.0 


5.0 


32.0 


40.0 


15.0 


79.0 


6.0 


5.0 


27.0 


45.0 



12.(1 

44.0 

2.0 

2.0 



TABLE IV. 



DETAILED ANALYSES OF BREAD GRAINS. 







"s 




e 






!i 


1 




1 




1 


^ 



Analyst. 



WHEAT. 



FromElsoss 

" Saxony. 

" America 

" Flanders.... 

" Odessa 

" Tanganrock 

" Poland 

" Himgary 

" Egypt 

From Hessia 

" Fi-ance 

" Saxony 



From Salzmiinde, Prussia 

Hushid, from Vienna. 
TJnlivjsked 



14.6 


59.7 


7.2 


1.2 


1.7 


1.6 


14.0 


11.8 


64.4 


1.4 


2.6 


2.5 


1.6 


15.6 


10.9 


63.4 


3.8 


1.2 


8.3 


1.6 


10.8 


10.7 


61.0 


9.2 


1.0 


1.8 


1.7 


14.6 


14.3 


59.6 


6.3 


1.5 


1.7 


1.4 


15.2 


13.6 


.57.9 


7.9 


1.9 


2.3 


1.6 


14.8 


21.5 


53.4 


6.8 


1,5 


1.7 


1.9 


13.2 


13.4 


62.2 


5.4 


1.1 


1.7 


1.7 


14.5 


20.6 


55.4 


0.0 


1.1 


1.8 


1.6 


14.8 







RYE. 








13.6 


50.5 


8.9 


0.9 


10.1 


1.8 


15.0 


11.6 


.56.5 


10.2 


1.9 


3.5 


2.2 


14.1 


9.1 


64.9 


0,4 


2.3 


3.5 


1.4 


18.3 


9.6 


56.7 


6.4 


2.1 


8.5 


3.3 


16.5 



BARLEY. 

10.5|.50.3[ 5.512.01 13.6 
4.22.6 
1.2|2.0| 
OATS. 
2.516.41 



13.253.7 
9.360.4 



11.5 
9.7 



I 8.8155.41 
15.73:2.2 
|10.2 ....| 



9.6 

....|....|6."i| i6!6 

BUCKWHEAT. 



Boussingault. 
Wunder. 
Poison. 
Peligot. 



Fresenius. 
Payen . 
A. Mijller. 
Wolfl". 



3. 8] 15. 7 1 Wolff. 
2.8 12.0 Poison. 
2.4|l5.0|Grouven. 

2.7114.6IA. MiJller. 
4.1 12.9 Krocker. 
2.7 12.6 Anderson. 



13.1 
8.5 
9.1 



37.8 
45.0 



7.1 
MAIZE. 



1.0 
1.3 
3.5 



22.0 



12.7 
13.7 
13.0 
14.2 
14.0 



From Saxony 

'' America.. . 

" Galacz 

" Switzerland 



8.8 


58.0 


5.3 


9.2 


4.9 


3.2 


10.5 


8.8 


54.4 


2.7 


4.6 


15.8 


1.7 


12,0 


9.1 


49.5 


2.9 


4.5 


20.4 


1.8 


11.8 


.... 


51.2 


6.7 


3.8 


12.5 


... 


10.6 



Bibra. 

BonssinMult. 
Horsford & Krockcr. 
Zenueck. 

Hellriegel. 
Poison. 

Bibra. 



APPENDIX. 389 

Detailed Analyses of Breai> GKAms. 



^c^ 






ArujUyst. 



From Piemont , 

" Patna 

" Piemont 

" East Indies.. 

Husked. Hagen an . 
" Nuxembei'o: 





EICE. 








7.5 .... 




0.5 


0.9 


0.5 


14.6 


7.2 79.9 


1.6 


0.1 


0.5 


0.9 


9.8 


7.8 .... 




0.2 


3.4 


0.3 


13.7 


5.9 73.9 


2.3 


0.9 


2.0 




14.0 



MILLET. 

|20.61....|....13.0| 
10.3 57.011.0 8.0 



2.4 
2.0 



BoussingaiLlt. 
Poison. 
Peligot. 
Bibra. 



|2.2|14.01Boussingault. 

... 12.2 Bibra. 



TABLE V. 

DETAILED ANALYSES OF POTATOES, by GROUVEif. 
{Agricultur- Chemie., 2te Auf., pp. 495 & 355.) 





White Potatoes, newly duff, 


Various Sorts. Aver- 




unmaniired. 


manured. 


age of 19 Analyses. 


Water 


74.95 

0.471 

0.04 1 oil 

0.29 f " 

1.31J 

0.76 

2.00 

0.07 
17.33 

1.90 

0.88 


78.01 
0.891 
0.03 o iq 

0.25 r-3-19 
2.O2I 
1.56 
1.50 
0.05 
13.40 
1.24 
1.05 


76.00 






Casein 


2.80 


C41iadin & Miiciclin C^) 








1.81 


Org. Acids 




Fat 


0.30 


Starch. 

Cellulose 

Ash 


15.24 
1.01 
0.95 








100. 


100. 





TABLE VI. 

DETAILED ANALYSES OF SUGAR BEETS. 



Hohenheim 

Moeckem 

" 2 lbs 

Bickendorf, 1^4 lbs. 



Slanstiidt, 2 lbs. 
Lockwitz, 134 lbs. 



Tharand, IH " manured. 



" 8U " " 

4 " " 

Sile.5ia, luimannred 

" manured witJi nitrate of soda 
' ' man' d with phosphate of lime 



Average. 



81.5 
&4.1 
81.7 
9.5 
80.0 

80.0 
79.9 

82.7 
81.8 
82.1 
82.5 
84.4 
82.7 
84.1 



81.5 



^ 



0.87 
0.82 
0.84 
0.90 
0.70 

0.68 
0.65 
0.93 
1.16 
1.14 
1.05 
1.14 
1.42 
1 



0.93 



^ 



11.90 
9.10 
11.21 
12.07 
12.90 

13.37 
13.32 
12.34 
10.15 
9.25 
8.45 
9.80 
11.57 
9.82 



11.5 



1^ 



3.47 
3.90 



5.09 
5.00 



1.33 
1.05 
1.36 
1.52 
1.20 



5.21 
5.53 
3.24 
5.77 
6.36 
7.07 
3.96 
3.63 
4.04 



3.71 1. 



0.89 
0.99 
0.94 
0.88 
0.70 

0.74 

0.60 

0.79 

1.12 

1.15 

0.93 

0. 

0.68 

O.TT 



0.85 



Analyst. 



Wolff. 
Ritthausen. 



Grouven, 
Stockhardt. 



Bretschneider. 



390 



HOW CEOPS GEOW. 



^ ft CD 



PCR ^ 



^.^ 



PaoSS 



05 JO 



2. Q B 






1 






1=1 

i 




< •; 



CKOOOO 0000 cococo c» 

CI tn ot oi or en ot oi ot 

OI ox *>- O OT rf». 01 Ol *< 



03*1-05 

883 



(-IOSCO 
M-0< OD 
OlCiO 

ooo 



pop 
0} '>«>. »o 

12^ 



-3 00 -a 

jo O) ot 



0-3 03 CO 35 CK> 



OTOI^s 



to lO h-i -5 > 



5050 Ol ot 

^ OS -5 CO -I 

.*..oo coos 



ooo oo o 

O to CO CO ot t-^ 



ooo 

WOOt 



o 

00.^ «> CO 



O l-l 



oo 

btbt 

to M- 

to 03 



poo 

It^ OS '-1 

CO O05 



kis 



ooo oo 

ot "to to ot *>. 

ot -3 O p ot 

OS -1 <— ■ ~ 



ojoa: 



ocoto 



oi-'O 

C0 05 



too 

to OS 



Sugar. 



Free Add:\ 



Albuminoids. 



Pectin-bodies. 
Ch-ini, Orriaiiic 

Adds in 
Combination. 



Soluble Ash- 
ingredients. 



Total Soluble 
Matters. 



1^ *>-C0 

btU'rfi. 



O t" I-' 



\W§. 



J-i_Oip 

CDOtO 
OiOJOS 
OOIO 



^t: ^5 



)tOtO 

•bt"*" 
; JO *^ 
oio 



>o» 



op p- p 
bi ip bt OT Us 

I-' h&. oso to 



OS j: 

8^ 



)l-^0 

)'>b.bt 
; JO t-^ 

> CO ot 



p PUP P 

h^^ tO.Ot OS .t-i 



>''p3 3 
)-3 sD c:3 



lootp 
bo bo OS 



cpt •_ ot ■ ot ot 
OS te rfii. to to go 

05*1 .-lOO o 



OS 03 )f^ OS to 

i-^o 

!£>03 



i-i;C to 
OSOI Ot 
0-3-3 



Seeds. 



Skins and Cel- 
lulose. 



PiXtose. 



Inwluble As7i- 
ingredients. t 



Total Insoluble 
Matters. 



• 00 • OS- 

)^0 )-' Ot to 00 

to 05 -3 Ot -1 fe 



gS g^88 ^ 



88? 



88? 



8P 8p1 



^8 8 



88 888 8 



APPENDIX. 



391 



* [-10 

CO Sa C 



^3 

S 2 



WW 



>»:? 






6 00 



5 -< ?i ... 









V< CiOT 



00 



p 3 o 
Q r-'Q 

05 -'JQ 






w ►;• T'* :;;r t3 
5c CO a 2 re 






S. &■ 



s- 



S ^ 



93 



W g H 






00 COCZ) 
Ct or OI 



JO C3 



CO to 03 C» O 00 

lc>. O or -1 -:i or 

<=• CK CO -T O C5 

Ot O J:^ M> O C» 



-^tsojco 



oco <io w rf^ 

5C03 O 00 Jx 

00 lO o >s~ 



l-^l-l 000 



1-^00 
iooicci 






§2 2 S?Sc^ Bo 



Sugar.* 



Free Acid A 



11 



00 



00 



0)0 

OiOf 



OTIO 

M-CO 



Albuminoids. 



00 p p p 

or '*>. CO CO Or 

Gi» oi-'-J 

COO cocco 



tn O 00 C5 



O or >Ci>- 
CO Ot >!;.. 
t-^ o< *>- 



Pectin-bodies. 
Gum, Organic 

Acids in 
Combination. 



00 o p p 

coco br CO >(i. 
-3 C5 OT h-^ 



Soluble Ash- 
ingredients. 



) h-t 00 O OI o 






0500 «DO 



O CO O 

tt- »o o 
CO CO o 



Total Soluble 
3Iatters. 



coco 

t-l-CH 



I 0» CD 



v-'p 
o'crt- 



ool-^ 



O »0 OT 

CO CO >o 

O O H-i 

c;i *». o 



Sg g 



OiOc 



oop 

»p C5 tfe. 



Or hfi- )4x Or 

oi-i 5t o 



yS'A.'zw^ a^i^J Cel- 
lulose. 



Pectose. 



00 



3o 



000 
000 



— ^ www. 



00 

I5 



S or -3 

CO O rfi- 



Insoluble Ash- 
ingredients. X 



rf^CO-5 

Uioo 

CO rf^co 
JO oco 



O 05 tfk. -^ 
»o ^ i-i CO 



OOT • • 

WOT 

tt »o CO 

MIOS OCO 



i-t CO c;i 

Jo >-i or 



Toted Insoluble 
Matters. 



ocoo 
io'co 



2 ^g 



CO 



fsg 



2 g^^ JgS! 






^:3 



CC'iO 



§g ss gs§ s§s s 



si^ 



88 
SS 



88 
88 



392 



HOW CROPS GEOW^ 







tji-a^*- 


hb. 


rfs. 




^ 




vf^ 


}S^ 




ft^ 












c:y< 






i^ 


^ 




op 






^ 


White. Mataitfel. 
English Winter G 

P 

Sweet, red -near.. 


White table apple 
Borsdorfer 


1^ 




:: 


r 

i 


s^ 


Ap 
Handsome, rather 
Very delicate, larg 














- 


•-0 


1 






s 


^c1 8 










p 






. 


. ? 






i 


2.'^ g 










E 






















-2. 
































c-.^O, 
































Ij 






M- 








l-iM. 






-i 










K^ 


^ 


^SOT 


^w 


m^k; 




^r 






weft 


































^ 








^ 


^ 










■f? 




OCO-5 


-5C5 


OtO 




CK 


Or 




bi't-i 


Sugar* 




§?§2 




















o 




ODCO 




















o 










(-> 


O 




OO 






» 




Cl-tO 


MO 














Free Acid.A 




























Q 












4^ 










1 


O 


o 


r 






r 




O 




OO 


















>J^ 




coco 


Albuminoids. 


i^ 


^ 




JIfe 


_^ 




i 1 


^ 




g^ 




s 










Pectin-bodies. 


>t^ 


w 


OTCOCS 


tC OS 


.7^ 




CS 




out 


G-um, Organic 


§ 


1 


tig^ 


I* -7 


CS 


8 






CO 
CO 




85*:S 


rAcids in 
Combination. 


2 


O 


=> 






O 


o 




OO 


Soluble Ash- 




■i 


1 


[ 


t&S? 


IS 


I 


<^ 


% 






ingredients. 




•p^"- 












T^ 












io 


=> 












o 




iiO 


Totrd Soluble 
























Matters. 








y:' CO o 


~ o 


—1 or 










gs 



























2 O H- 



.- 


1 : : 


(-> r o ■ P .^"^ f* .^'^ 


Seeds. 


§' 


CO 


00 ; ; 




Skins and Cel- 
hdose. 


^ 
? 


p M- '■ '• 


: g §1 K.O 
S8 fe: I gfe 


Pectose. 


1 

1 


3 3 : : 


^^ ^z. 3 3 33 
PP P- 1-^ b ^b 


Insoluble Ash- 
itigredients.t 


i 




5.415 
5.266 

5.620 
9.184 

2.39 

3.27 

3.00 
2.96 

2.44 


Total Insoluble 
Hatters. 



OO 



88 88 



SS 
8§ 

OO 



APPENDIX. 



39( 



TABLE VIII. 



FKUITS AKRANGED IN THE ORDER OF THEIR CONTENT OF SUGAR, 

(average,) Fkesenius. 



•per cent. 

Peaches 1.6 

Apricots 1.8 

Plums 2.1 

Reineclaudes 3.1 

Mirabelles 3.6 

Raspberries 4.0 

Blackberries 4.4 

Strawberries 5.7 

Whortleberries 5.8 



•per cent. 

Currants 6.1 

Prunes 6.3 

Gooseberries 7.2 

Red pears 7.5 

Apples 8.4 

Sour cherries 8.8 

Mulberries 9.2 

Sweet cherries 10.8 

Grapes 14,9 



TABLE IX. 

FRUITS ARRANGED IN THE ORDER OF THEIR CONTENT OF FREE 
ACID EXPRESSED AS HYDRATE OF MALIC ACID, (average,) Fresenitjs. 



•per cent. 

Red pears 0.1 

Mirabelles 0.6 

Sweet cherries 0.6 

Peaches 0.7 

Grapes 0.7 

Apples 0.8 

Pranes 0.9 

Reineclaudes 0.9 

Apricots 1.1 



per cent. 

Blackberries 1.2 

Sour cherries 1.3 

Plums 1.3 

Whortleberries 1.3 

Strawberries 1.3 

Gooseberries... 1.5 

Raspberries 1.5 

Mulberries 1.9 

Currants, 2.0 



TABLE X. 

FRUITS ARRANGED ACCORDING TO THE PROPORTIONS BETWEEN 
ACID, SUGAR, PECTIN AND GUM, ETC., (averages,) Feesenius. 



Plums 

Apricots 

Peaches 

Raspberries..., 

Currants 

Reineclaudes.. 
Blackberries. . . 
Whortleberries 
Strawberries . . 
Gooseberries . , 

Mulberries 

Mirabelles 

Sour cherries.. 

Prunes 

Apples 

Sweet cherries. 

Grapes 

Red pears 

17* 



Acid. 



Sugar. 



7.0 
11.2 
17.3 
20.2 
94.6 



Pectin, Gum, etc. 



3.1 
6.4 

11.9 
1.0 
0.1 

11.8 
1.2 
0.4 
0.1 
0.8 
1.1 
9.9 
1.4 
4.4 
5.6 
2.8 
2.0 

44.4 



sot 



HOW CEOPS GROW. 



TABLE XI. 

FEUITS ARRANGED ACCORDING TO THE PROPORTIONS BETWEEN 
WATER, SOLUBLE MATTERS AND INSOLUBLE MATTERS, 

(averages,) Feesenius. 



■ 


Water. 


SoluUeMdtters. 


TmoluhU Matters. 




100 
100 
100 
100 
100 
100 
100 
100 
100 
103 
100 
100 
100 
100 
100 
100 
100 
100 


9.1 
9.3 
9.4 
9.7 
11.0 
12.1 
12.2 
13.0 
13.3 
14.3 
14.6 
15.3 
16.5 
16.6 
16.9 
18.5 
18.6 
22.8 


6 9 


Blackben-ies 

Strawbemes 


6.5 
5 2 


Plums ... 


9 


Currants 


6.6 




16.9 




3 6 




1 5 


Apricots 


2.1 


Red pears 

Peaches 


5.5 
2.1 


Prunes , 


3 2 


flour cheri'ies .'.... 


1 3 


Mulberries. 


1 5 


Apples 


3 6 


Reineclaudes 

Cherries , 

Grapes 


1.2 
1.5 

5.8 



TABLE XII. 

PROPORTION OF OIL IN VARIOUS A.IR-DRY SEEDS, accordiug to Beejot. 

{Knoifs Agricultur CJiemie^ p. 725.) 

(The air-diy seeds contain 10-12 per cent of hygroscopic water.) 

Gold of Pleasure 85 

Watermelon 36 

Charlock 15^2 



Colza, 



common 40-45 

" ScJiirmraps 44 

" red India 40 

" -white " 40 

Flax 34 

Poppy 40-50 

Sesame 53 

Mustard, white 30 

'' black 29 

Hemp 28 

Pean at 38 



Orange 40 

Colocynth 16 



42 
40 
16 
16 
26 
Beechnut 34 



Cherry .... 

Almond 

Potato 

Buckthorn. 
Currant 



DARWIN'S NEW WORK. 



THE VAISIAXION 



ANIMALS AND PLANTS 



UNDER DOMESTICATION. 

BT 

CHARLES i>AE,-wii>^, m:._a.., if.r.s., etc. 
AUTHORIZED EDITION. 

■^T^ITiaC -^ I' DFt :E3 DE' ^<SL O 13 

BY 

PROFESSOR ASA GRAY. 

This work treats of the variations in our domestic animals and cultivated 
plants, discussing the circumstances that influence these variations, inherit- 
ance of peculiarities, results of in-and-in breeding, crossing, etc. 

It is one of the most remarkable books of the present day, presenting an 
array of facts that show the most extraordinary amount of observation and 
-esearch. All the domestic animals, from horses and cattle to canary-birds and 
noney-bees, are discussed, as well as our leading culinary and other plants, 
making it a work of the greatest interest. 

Its importance to agriculturists, breeders, scientific men, and the general 
reader will be seen by its scope as indicated in the following partial enumera- 
tion of its contents : Pigs, Cattle, Sheep, Goats ; Dogs and Cats, Horses 
AND Asses ; Domestic Rabbits ; Domestic Pigeons ; Fowls, Ducks, Geese, 
Peacock, Tukkey, Guinea Fowl, Canakt-bird, Gold-fish ; Hive-bees ; 
Silk-moths. Cultivated Plants ; Cereal and Culinart Plants ; Fruits, 
Ornamental Trees, Flowers, Bud Variation. Inh:eritance, Reversion 
or Atavism, Crossing. On the Good Effects op Crossing, and on the 
Evil Effects of Close Interbreeding. Selection. Causes of Vajriabil- 
ITY, Laws of Variation, etc., eto. 

PiiblisUed in Two Volumes of nearly 1100 pages. 

EIlSrEr^Y ILLTISTR^TED. 
SENT POST-PAID, PRICE, $6.00. 

ORANGE JUDD & CO., 

245 Broadway, New -York City. 



GARDENING FOR PROFIT, 

In the Market and Family G-arden. 
By Peter Henderson. 

This is the first work on Market Gardening ever published m this 
country. Its author is well known as a market gardener of eighteen 
years' successful experience. In this work he has recorded thia 
experience, and given, without reservation, the methods necessary 
to the profitable culture of the commercial or 

]\XA.IlIi:ET GJlI1I>E]V. 

It is a work for which there has long been a demand, and ono 
which will commend itself, not only to those who grow vegetables 
for sale, but to the cultivator of the i 

FAMILY GARDEN, 

to whom it presents methods quite different from the old ones gen- 
erally practiced. It is an original and purely American work, and 
not made up, as books on gardening too often are, by quotations 
from foreign authors. 

Every thing is made perfectly plain, and the subject treated in all 
its details, from the selection of the soil to preparing the products 
for market. 

CONTENTS. 

Men fitted for the Business of Gardening. 

The Amoiint of Capital Kequired, and 

"Working ij'orce per Acre. 

Profits of Market Gardening. 

Xiocation, Situation, and Laying Out. 

Soils, Drainage, and Preparation. 

Manures, Implements. 

Uses and Management of Cold Frames. 

Formation and Management of Hot-bedg. 

Forcing Pits or Green-houses. 

Seeds and Seed Raising. 

How, "When, and WTiere to Sow Seeds. 

Transplanting, Insacts. 

Packing of Vegetables for Shipping. 

Preservation of Vegetables in Winter. 

Vegetables, their Varieties and Cultivation. 

In the last chapter, the most valuable kinds are described, and 
the culture proper to each is given in detail. 

Sent post-paid, prico $1.50. 
OEANGE JUDD & CO., 245 Broadway, New-York. 



